σ

Sigma 

Agricultural Risk 

and Actuarial 

Services, LLC 

Review of the Pasture, Rangeland, 

Forage Rainfall Index Crop 

Insurance Program Indexing and 

Rating Methodology Final Report

June 18, 2020

Authors: Keith Coble, Barry 

Goodwin, Mary Frances Miller, 

Rod Rejesus, Ardian Harri, and 

Daniel Linton
i 

Executive Summary

There are two primary objectives of this task order. First, we were asked to review the 

County Base Values (CBV) for the Pasture, Rangeland, Forage Rainfall Index (PRF-RI) 

crop insurance program. Secondly, we were asked to conduct a comprehensive review 

of the methodology and calculations used in the determination of the rainfall index and 

associated premium rates. In both cases, we were asked to provide assessments of the 

current program, recommendations for changes, or any other improvements that we 

recommend RMA consider. 

A review of loss experience for the PRF rainfall index plan of insurance shows that the 

overall actuarial performance of the PRF plan of insurance has been strong. The loss 

ratio only exceeded 1.0 in three of the 13 years of experience. The summaries also 

make clear another point. The rate of indemnification (claims frequency) is very high 

for the PRF plan. The results indicate that 70-90 percent of policies had a claim. The 

high frequency coupled with overall very good actuarial performance probably 

indicates that the program suffers from a great deal of frictional cost: a high frequency 

of small losses that in most cases provide only a partial return of premium. It seems 

reasonable for RMA to explore program modifications that reduce frequency, possibly 

with offsetting increases in benefits for remaining claims, to better meet the needs of 

growers.

Overall, we find the CBV calculation methods used for each intended use covered in 

the PRF insurance contract (e.g., non-irrigated hay, irrigated hay, and grazing) to be 

appropriate. We believe that the conceptual basis for the CBV values are sound. It 

seems reasonable for RMA to at least explore whether it is feasible to apply a minimum 

CBV value that is equal to a county-level or state-level measure of pastureland cash 

rent. 

In the current CBV methodology, NRCS Hybrid Productivity Model (HPM) derived 

productivity factors are utilized in the non-irrigated haying and the grazing CBV 

calculations. In particular, a “district-state” productivity factor is used for calculating 

the non-irrigated haying CBV, and a “county-state” productivity factor is used for 

computing the grazing CBV. These factors were derived based on the NRCS HPM 

model so that estimates of the district-level non-irrigated haying CBV and the countylevel grazing CBV are consistent with the inherent “productivity” of the pasture at these 

levels of geographic aggregation. The use of these productivity factors somewhat 

assures that the estimated CBVs at these levels are consistent with the inherent capacity 

of the land to produce pasture in these areas. Aside from the NRCS HPM, the U.S. 

Forest Service’s “Rangeland Vegetation Simulator” (RVS) is an alternative. It seems 

that output from this model can serve as an alternative data source to validate the 
ii

productivity values generated from the NRCS HPM. 

We provide a review of scientific literature related to the pasture and rangeland 

insurance product. In general, this is a growing body of literature, with significant 

contributions in recent years. We include a discussion of recent advances in index 

insurance. Further, several recent papers specifically focus on the PRF program. 

The current procedure used in rating the PRF product utilizes a nonparametric empirical 

burn rate and parametric distributions derived from the log-normal and the truncated 

normal. Because there are currently only 70 years of rainfall data available (in the CPC 

data currently used by RMA), the use of an empirical burn rate might be questionable. 

We believe that there is an error in the formula used to derive the BS/lognormal rates in 

the RMA rating program. We examined the formula and believe there is a simple 

correction. However, it will generally lower rates. 

Our review of the PRF product leads us to make the following recommendations. 

1. Validating the HPM productivity factors against alternative models 

The U.S. Forest Service’s “Rangeland Vegetation Simulator” can serve as an alternative data 

source to at least validate the productivity values generated from the NRCS HPM. 

Comparisons of the resulting CBV values from the RVS vis-à-vis the NRCS HPM can be 

conducted to see if there are any large discrepancies in the estimates. In the end, exploring an 

alternative source for productivity values can help improve the robustness of the CBV 

estimates. 

2. Modification of the County Based Value (CBV)

Currently, there is no set minimum value for the district-level grazing CBVs used in the PRF 

contract. Therefore, it is possible for the district-level grazing CBV (used for a particular 

county) to be lower than the estimated NASS county-level pasture rental rate. Newton 

(2018), for example, has shown that there are cases in South Dakota where 2019 CBVs were 

up to 46 percent lower than NASS state-level pastureland rent in 2018. Based on research 

cited in our exploration of the CBV, we recommend RMA apply a minimum CBV value that is 

equal to a county-level or state-level measure of pastureland cash rent (perhaps in a 

previous year or based on historical average). Applying this minimum (in conjunction with 

the other changes recommended in this report) may improve the risk mitigation benefits from 

the PRF product. 

We also recommend partitioning the CBV for the grazing type into improved pasture and 

rangeland, with the distinction being that improved pastures are managed and that 

“Management usually consists of cultural treatments: fertilization, weed control, reseeding”. 

The productivity differential estimates from the papers cited in this report indicate that a 
iii

rangeland-pastureland factor in the range of 60%-70% is justifiable as a “conservative” 

measure (especially in the Western States where there is a good mixture of unmanaged 

rangelands and managed pastureland). Hence, the State-level grazing CBV yield estimate can 

be adjusted downward by 30%-40% for insureds that self-select and say that their PRFinsured land is unmanaged rangeland. On the other hand, the State-level grazing CBV yield 

estimate can be adjusted upward by 30%-40% for insured that self-selects and say that their 

PRF-insured land is managed pastureland. 

Notwithstanding this recommendation for adjusting the State-level grazing yield in the 

grazing CBV calculations, the recommendation in this report of using a minimum grazing 

CBV value based on pastureland rents should still serve as the “floor” on the calculated 

CBV. That is, if the resulting district-level CBV with the downward adjustment (due to using 

unmanaged rangeland) is lower than the minimum CBV based on pastureland rental rates, 

then the minimum CBV based on pastureland rental rates will be the applicable one.

3. Adjusting the CBV Productivity Range

With improvements in the CBV calculations over the last five years (that improves accuracy 

and precision) and implementation of the minimum grazing CBV above (Recommendation 

2), we believe that it is appropriate to reduce the range of available productivity factors in the 

PRF insurance offering. Similar area-based insurance plans offered by RMA that triggers on 

a county-yield “index”, such as the Area Risk Protection Insurance (ARPI), only have a 

productivity range between 0.8 and 1.2 (as compared to the 0.6 to 1.5 range in PRF). Hence, 

for consistency across index-based RMA product offerings and to align better with risk 

minimization behavior, we suggest narrowing the productivity factor to the 0.8 to 1.2 range. 

4. Continue Using the NOAA CPC Data

RMA should continue to use the NOAA CPC precipitation data. Alternative data sets 

(PRISM, NCEI, NEXRAD, NCDC) offer no real advantages and, in the case of the NCEI, a 

disadvantage in that the data are not “gridded” but rather are reported at the station level. 

The absence of any “ground-truthing” obviates any tangible approach to selecting one data 

set over another on the grounds of accuracy. Ultimately, we recommend no changes to the 

current data used to rate and design coverage. Although trends and structural breaks are 

sometimes identified in the precipitation data, such changes over time are always small and 

are not consistent across different grid IDs. Climatologists have provided substantial 

evidence of trends in temperature and intensity of storms. Our analysis suggests the amount 

of rainfall over a two-month period has not changed significantly. We recommend that 

RMA continue to use the full 1948-present CPC data in its entirety and without explicit 

adjustments meant to reflect climate change.
iv

5. Actuarial Sufficiency

Overall, this program is actuarially sound. Outside of a computation error in fitting the 

Black Scholes parameters, we find no significant shortcomings in the general approach used 

by RMA to estimate premium rates. Methods currently used to bound rates and to select the 

final rates from among the different rate estimates are ad hoc. We recommend that RMA 

consider the use of goodness-of-fit tests in the selection of the final parametric distribution 

used to estimate rates. Of course, rates derived from parametric distributions should be 

compared to empirical burn rates. The truncated normal distribution is strongly supported in 

a majority of cases. Procedures currently used to spatially smooth rates are appropriate and 

we recommend no changes to these procedures. 

 

In some cases with extremely high or low variance, convergence issues may make it 

difficult to adequately estimate parametric rates and thus any measure based on such rates

needs a careful review. We find a connection between rating and our next recommendation. 

Some grids/interval combinations result in extremely high rates (greater than 50%). This 

typically occurs in extremely dry grid/intervals (See page 78). RMA has sometimes 

excluded a county if any interval rate is above 50% in that county. We recommend this rule 

be made permanent for all regions. It will improve rating accuracy and augment 

recommendation 6. 

6. Focusing PRF on Viable Forage Production Areas 

As mentioned in recommendation 5, we believe eliminating counties where rates exceed 50 

percent will focus the program on viable regions. If RMA prefers to eliminate whole 

counties from the program based on the suitability of soil and climate conditions for forage 

production, we recommend consideration of the land capability classification. Specifically, 

we recommend dropping counties having more than 50% of the total area that falls into land 

capability class 8 and/or subclass C. Such land has been designated by NRCS to be 

unsuitable for cultivation. A review of the 2017 census indicates that only a very small 

proportion of land in such counties is used to harvest forage or hay. This recommendation 

comes with two caveats. First, eliminating entire counties may not be appropriate in areas 

where land quality is very heterogeneous. This reflects the lack of resolution in a county 

aggregate. Second, as is likely to be the case with any threshold criteria, the choice of 50% is 

admittedly arbitrary but is justified in light of the very limited acreage devoted to hay in 

forage in such areas. 

If RMA is willing to consider a higher degree of resolution and instead eliminate individual 

grid points rather than entire counties, we believe that the USFS measures of forage 

production provide an ideal metric for selecting areas to drop from coverage. We have 

obtained a direct measure of average forage production for each grid point and have 
v 

demonstrated the strong correspondence between precipitation and forage production. 

Again, one can infer that, depending on the threshold selected, this would affect few 

producers of forage and rangeland. This is again demonstrated by the fact that forage 

production is low, in terms of both output and acreage, in such areas. Once again, the 

threshold of rangeland production that defines dropping a grid point from the PRF plan is 

arbitrary but is directly justified by the very low level of forage production and 

concomitantly low allocation of acreage to forage in such areas. 

In summary, we recommend that RMA drop any grid point and its relevant 0.25-degree 

surrounding area that corresponds to the lowest 1-percentile of the distribution of forage 

production from eligibility for PRF coverage. This would eliminate 96 of the 13,626 grid 

points currently in the program. We have outlined alternative thresholds that could be used 

to eliminate marginal forage producing areas and believe that these may form the basis for 

future program revisions. A less drastic step would be to allow insurance in these areas, but 

with a reduced CBV and to allow irrigated acres to insure. We note that we also considered 

eliminating intervals with extremely high rates. This is an actuarial approach, but we believe 

that it is also a practical approach to the problem. 

7. Better Targeting of Indemnities

Our review leads us to conclude that the current program frequently pays for shallow losses 

that are likely not significant financial threats while at times not sufficiently compensating 

for deep losses that are often a part of widespread droughts driving up replacement forage 

costs. We believe the program can become a better risk management tool, based on the 

evidence we find of a relationship between the replacement cost of forage and deep losses. 

We recommend dropping the maximum coverage level to 80 percent while also adding a 

disappearing deductible and adjustment to enhance indemnities when in an extreme loss 

situation. One could develop more elaborate drought triggers, but they add significant 

complexity. For the sake of operational simplicity, we believe the indemnity function should 

be in the form of a disappearing deductible and perhaps reflect an accelerated disappearing 

deductible. 

8. Focusing coverage on risk-reducing intervals. 

Our team reviewed a variety of resources and scientific studies focusing on forage and range 

production practices. We also conducted statistical analysis of the relationship of measured 

forage production to monthly rainfall amounts. We find that there is wide variation in the 

relevant rainfall months due to forage species, production system, location, and rainfall 

patterns. However, we do find that with rare exceptions, there are no more than eight months 

in a year that have a significant rainfall effect. In some cases, the key months may be 
vi

preseason or postseason replenishment for the following year. However, in a county-bycounty analysis, we found 1,638 counties (96.35%) have 5 or fewer months of significant 

precipitation effect. For the Western states, 83.93% have only 3 or fewer months of 

significant precipitation effect.

We believe this provides strong evidence of two things. First, there is evidence in the forage 

literature and our analysis that producers risk management would be best served by focusing 

the value of the policy on the months that pose the greatest production risk. Spreading value 

within a year across extraneous intervals increases basis risk in the PRF product. However, 

because production systems sometimes vary even within a county, we believe producers may 

need the flexibility to choose the periods that best fit their operation and reduce the basis risk 

for their farm. 

In the Pasture, Rangeland, Forage (PRF) Crop Provisions, section 2. (a) 

states:

2. Application

(a) In addition to the provisions contained in section 2(c)(1) of the Basic Provisions, a 

percent of value must be allocated to more than one index interval for each grid ID, intended 

use, irrigated practice, and share. The minimum percent of value allowed in any one index 

interval by grid ID, intended use, irrigated practice, and share is 10 percent. The 

maximum percent of the value that can be allocated to any single index interval by grid ID, 

intended use, irrigated practice, and share is specified in the Special Provisions. 

We note that this minimum is well below the value that would allow insuring six periods in a 

year (16.6%). Ultimately, we recommend increasing the minimum percentage of value in 

any one index interval to 25 percent. This will allow insuring eight months of a 12 month 

period. (If intervals are widened to three-month intervals we suggest a 33 percent minimum 

value so that no more than nine months can be covered.) This will require producers to 

focus participation in periods that most affect production. We also believe a strong 

education program is needed for producers and agents to help the producer to achieve value 

allocations most correlated with their risk. 

9. An Alternative Approach to Reducing Frequent Shallow Losses.

Recommendation 9 is offered for consideration only if the coverage level aspect of 

recommendation 7 is not adopted. We demonstrate in this report that modifying the 

program such that three-month periods are used rather than two-month periods reduces 

payment frequency roughly the same as reducing coverage by 5 percent. We see no 

significant effect on risk reduction, and potentially this change makes the program simpler if 

there are fewer periods. However, if a producer has a tight window of relevant rainfall risk 

than a three-month period this will in a sense require covering unneeded periods. 
0 

Contents

Executive Summary........................................................................................................................................ i

Chapter 1 Introduction ................................................................................................................................. 2

Objective: .................................................................................................................................................. 2

Scope:........................................................................................................................................................ 2

Background of the Program...................................................................................................................... 2

Discussion of Prior Experience................................................................................................................... 5

Pasture and Rangeland Production Systems..........................................................................................17

Chapter 1 References ..............................................................................................................................22

Chapter 2 Task 1: A comprehensive review of the County Base Values ....................................................24

Current CBV Methodology (2020) ..........................................................................................................24

Non-irrigated Haying CBV........................................................................................................................24

Irrigated Haying CBV................................................................................................................................25

Grazing CBV .............................................................................................................................................26

Rangeland and Pastureland CBV differences ..........................................................................................27

Observations, Analysis, and Recommendations.....................................................................................28

Setting a minimum grazing CBV: County-level NASS pasture rental rate data .......................................29

Validating the HPM productivity factors against an alternative model ..................................................30

Minor clarifications to the irrigated hay CBV and the grazing CBV procedure .......................................31

Adjusting the productivity factor limits given the CBV calculation improvements?...............................32

Main CBV Recommendations..................................................................................................................34

Chapter 2 References ..............................................................................................................................35

Chapter 3 Task 2: A review of the methodology used for the PRF rainfall index and premium rates. .....38

Pasture and Rangeland Literature Review..............................................................................................38

Origins of index insurance .......................................................................................................................38

Rating PRF insurance ...............................................................................................................................41

Demand for PRF insurance ......................................................................................................................42

Advances in index insurance since 2010 ................................................................................................. 45

Chapter 3 References: .............................................................................................................................49

Chapter 4 Review and analyze the methods used in the development of the expected rainfall amount . 57

Discussion of Data...................................................................................................................................57
1 

Trend Analysis.........................................................................................................................................60

Data Recommendations..........................................................................................................................60

Rating Review..........................................................................................................................................75

Actuarial Recommendations...................................................................................................................91

Chapter 5 Evaluate the current program design ........................................................................................92

Assessment of the frequency of payments.............................................................................................92

Intervals contributing to forage production............................................................................................99

Assessment of the relationship between hay yields and weather variables ..........................................99

Chapter 6 Targeting PRF to Viable Regions...............................................................................................121

PRF Viable Regions Recommendations................................................................................................. 123

An alternative approach based on the percent of annual rainfall........................................................138

Chapter 7 Improving the PRF loss function and weather variables ..........................................................151

The relationship of forage losses with replacement value...................................................................151

Assessment of the relationship between alfalfa hay prices and yields and weather variables............153

Chapter 7 References ............................................................................................................................153

Mitigating forage replacement cost with a disappearing deductible...................................................162

Recommendation: Targeting Indemnities to make PRF a better risk management tool.....................165

Chapter 7 References: ...........................................................................................................................170

Appendix 1: Summary of CBV Calculation Steps...................................................................................171

Non-irrigated Haying CBV Calculation...................................................................................................171

Irrigated Haying CBV Calculation...........................................................................................................172

Grazing CBV Calculation.........................................................................................................................172

Appendix 2 Price Yield Relationship......................................................................................................174

Appendix 2 Station IDs With LCC 8/U > 50% of Land Area ...................................................................180

Appendix 3 Station IDs With Forage Production < 1st Percentile ........................................................181
2 

Chapter 1 Introduction

Objective: 

There are two primary objectives of this task order. First, we were asked to review the 

County Base Values (CBV) for the Pasture, Rangeland, Forage Rainfall Index (PRF-RI) 

crop insurance program. The CBV essentially provides the liability associated with this 

index-based product. Secondly, we were asked to conduct a comprehensive review of 

the methodology and calculations used in the determination of the rainfall index and 

associated premium rates. In both cases, we were asked to provide assessments of the 

current program, recommendations for changes, or any other improvements that we 

recommend RMA consider.

Scope:

For each task listed below, this order will involve submitting two reports after the 

contractor conducts the necessary research to accomplish the specific tasks and work 

requirements listed. The tasks have been conducted simultaneously. The work will involve 

data collection, review and analysis (including a review of any relevant academic research 

publications or articles), and report writing. 

Background of the Program

The PRF-RI crop insurance program is an area plan of insurance based on an index of 

historical rainfall for specific two-month periods called index intervals. The index is 

normalized such that 100 is approximately equal to the historical average of rainfall from 

1948 to the past year. 

PRF-RI utilizes a grid system rather than a county value like other area plans of insurance. 

The PRF-RI grid system is based on data produced by the National Oceanic and 

Atmospheric Administration Climate Prediction Center (NOAA CPC). Indemnities are

payable when the final grid index falls below the trigger grid index for the two-month 

index interval. The trigger grid index equals the expected grid index (100) times the 

coverage level chosen by the producer. 

A producer has three primary choices for participation. First, they may select one 

coverage level from 70 percent through 90 percent for the county, crop, intended use, 
3 

irrigated practice, and organic practice. Second, they may select only one productivity 

factor from 60 percent through 150 percent for the county, crop, intended use, irrigated 

practice, and organic practice. Third, a producer must select at least two index intervals 

but may select up to six index intervals. Once the intervals are chosen then they are 

required to allocate at least ten percent of value to each interval.

One of the complexities of this product relates to the fact that the growing season is not 

necessarily when precipitation is important for forage growth. In particular, preseason 

weather can affect forage growth. Another challenge is driven by the differences in the 

growing season for different species. Further, production systems may use these different 

growing seasons to even out the supply of forage.

Figure 1-1. shows the aggregate number of policies earning premium and the policies 

indemnified for 2010-2019. First, there has been a threefold increase in policies. 

Secondly, the number of polices indemnified is often nearly as high as the number of 

policies earning premium. The percentage is at least 70 percent and in some years as 

much as 91 percent of polices earning a premium received an indemnity for a least one 

index period. 

Figure 1-1 

Figure 1-2 shows the growth in acreage in the Rainfall Index product. Acreage has grown at a 

faster rate than policies earning premium in the last decade. The acres insured in the program 

has increased five-fold and exceeded 140 million insured acres in 2019. As a point of reference, 

the 2019 acreage for rainfall insurance is approximately double that of soybeans. 

0

5000

10000

15000

20000

25000

30000

35000

40000

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Policies Earning Prem Policies Indemnified
4 

The actuarial performance of the program is shown in figure 1-3. While 2019 data may be 

preliminary, there is a clear indication that only one year (2011) has a loss ratio that 

substantially exceeds 1.0. Overall, the aggregate loss ratio for the decade is 0.85. 

Combined with Table 1-1, we conclude that it is an actuarially sound program with frequent 

indemnities. The frequency stems because a producer essentially has up to six index periods 

that potentially may trigger an indemnity in a year. However, it appears the program is 

rated correctly and collects sufficient premium. The fact that the plan pays indemnities on 

70-90 percent of policies, coupled with a significant premium subsidy, means that PRF 

coverage is likely to frequently pay indemnities above the subsidized premium. 

 -

 20,000,000

 40,000,000

 60,000,000

 80,000,000

 100,000,000

 120,000,000

 140,000,000

 160,000,000

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Acres Insured

Figure 1-2
5 

Figure 1-3

Table 1-1 summarizes the percent of total acreage insured at various coverage levels during 

2010-2019. The most popular coverage level is the 90 percent coverage and the second 

most popular is 85 percent coverage. Combined, the top two coverage levels account for 

more than 70 percent of insured PRF acres. The only other coverage level of significance is 

the 75 percent coverage. Policies at the 65 percent coverage level are a very small portion 

of insured acres. 

Table 1-1 

COVERAGE PERCENT OF 

INSURED ACRES

65% 0.004%

70% 2.35%

75% 24.36%

80% 2.05%

85% 33.44%

90% 37.80%

Discussion of Prior Experience

Table 1-2 presents a summary of business over the history of the PRF rainfall index plan of 

insurance. Table 1-3 presents a summary of business across states. These summaries 

highlight two important points. First, the overall actuarial performance of the PRF plan of 

insurance has been strong. The loss ratio only exceeded 1.0 in three of the 13 years of 

experience and the aggregate loss ratio across all years is 0.85. The program is actuarially 

sound

 -

 0.20

 0.40

 0.60

 0.80

 1.00

 1.20

 1.40

 1.60

 1.80

2010 2011 2012 2013 2014 2015 2016 2017 2018 2019

Loss Ratio
6 

Table 1-2. Summary of Business for PRF by Year

County Loss Loss

Pol 

Indem Unit Indem

Year Observations Liability Premium Subsidy Indem Acres Cost Ratio Rate Rate

2007 657 325,817,906 63,523,875 37,473,952 40,471,879 24,504,699 0.1242 0.6371 0.8156 0.3429

2008 822 309,449,519 60,075,919 35,528,830 79,189,613 23,065,184 0.2559 1.3182 0.9520 0.5883

2009 1106 445,582,606 85,549,325 46,394,694 43,972,078 33,576,725 0.0987 0.5140 0.7447 0.3164

2010 1237 370,635,267 77,295,912 42,174,296 55,124,485 27,750,078 0.1487 0.7132 0.7670 0.3065

2011 1902 480,996,764 105,176,184 57,394,647 178,394,556 30,977,432 0.3709 1.6962 0.8124 0.6156

2012 2374 743,734,976 156,593,505 84,907,799 162,225,446 44,028,691 0.2181 1.0360 0.9500 0.5673

2013 3176 936,048,488 187,954,873 100,932,509 157,761,695 49,637,100 0.1685 0.8394 0.8442 0.4536

2014 3149 911,932,503 189,225,864 101,434,295 164,826,648 46,961,303 0.1807 0.8711 0.8304 0.4939

2015 3152 973,376,596 200,322,890 107,304,397 101,483,846 47,952,812 0.1043 0.5066 0.8000 0.3149

2016 3807 1,390,820,805 280,794,245 151,276,230 178,756,107 51,792,278 0.1285 0.6366 0.8529 0.3821

2017 4148 1,744,753,278 380,380,725 202,997,207 341,240,501 74,936,300 0.1956 0.8971 0.9161 0.4565

2018 4592 2,378,024,087 520,182,283 278,223,896 500,039,152 98,288,987 0.2103 0.9613 0.7900 0.4061

2019 4806 2,625,920,558 581,849,617 310,489,756 291,559,417 140,392,732 0.1110 0.5011 0.6924 0.3044
7 

Table 1-3. Summary of Business for PRF by State

County Loss Loss Pol Indem

Unit 

Indem

Year Years Liability Premium Subsidy Indem Acres Cost Ratio Rate Rate

Alabama 1279

 

194,173,260 

 

25,223,506 

 

13,046,941 16,009,002 

 

1,323,210 0.082 0.635 0.741 0.380

Arizona 232

 

1,211,174,726 

 

354,954,154 

 

187,329,797 248,453,812 

 

97,979,353 0.205 0.700 0.660 0.363

Arkansas 711

 

141,448,552 

 

21,101,887 

 

11,159,446 11,149,390 

 

1,000,937 0.079 0.528 0.661 0.271

California 931

 

529,092,833 

 

153,387,468 

 

83,430,636 112,252,895 

 

27,273,848 0.212 0.732 0.724 0.471

Colorado 1335

 

811,446,609 

 

170,165,702 

 

89,019,127 133,023,522 

 

35,550,623 0.164 0.782 0.738 0.404

Connecticut 14

 

514,006 

 

48,615 

 

26,491 12,761 

 

1,439 0.025 0.262 0.400 0.180

Delaware 4

 

71,869 

 

8,358 

 

4,265 2,592 

 

151 0.036 0.310 0.400 0.188

Florida 696

 

937,704,554 

 

195,525,483 

 

99,708,323 159,605,498 

 

9,695,132 0.170 0.816 0.757 0.478

Georgia 1223

 

160,810,467 

 

23,452,034 

 

12,003,910 14,462,874 

 

1,090,480 0.090 0.617 0.639 0.360

Idaho 326

 

158,459,187 

 

33,681,048 

 

18,060,585 15,250,904 

 

6,727,359 0.096 0.453 0.384 0.227

Illinois 441

 

44,610,166 

 

6,041,285 

 

3,203,698 2,402,370 

 

181,181 0.054 0.398 0.421 0.184

Indiana 324

 

21,504,537 

 

2,556,956 

 

1,336,965 708,612 

 

91,297 0.033 0.277 0.501 0.196

Iowa 363

 

24,942,607 

 

3,599,941 

 

1,888,135 1,081,196 

 

214,660 0.043 0.300 0.489 0.232

Kansas 2596

 

415,382,517 

 

78,585,453 

 

41,622,187 35,990,280 

 

9,546,460 0.087 0.458 0.610 0.278

Kentucky 575

 

114,142,198 

 

14,132,077 

 

7,242,781 5,357,827 

 

578,629 0.047 0.379 0.516 0.201

Louisiana 231

 

37,443,848 

 

6,070,193 

 

3,118,848 3,189,690 

 

309,767 0.085 0.525 0.671 0.269

Maine 1

 

43,188 

 

3,868 

 

1,973 - 

 

294 0.000 0.000 0.000 0.000

Maryland 131 308,437 0.050 0.456 0.496 0.296
8 

County Loss Loss Pol Indem

Unit 

Indem

Year Years Liability Premium Subsidy Indem Acres Cost Ratio Rate Rate

6,130,947 676,424 357,636 18,896 

Massachuset

ts 36

 

2,708,929 

 

290,129 

 

159,022 115,065 

 

6,955 0.042 0.397 0.524 0.236

Michigan 168

 

20,611,542 

 

2,254,679 

 

1,165,370 645,042 

 

51,520 0.031 0.286 0.433 0.206

Minnesota 775

 

47,981,899 

 

7,047,258 

 

3,705,959 3,432,017 

 

402,331 0.072 0.487 0.597 0.304

Mississippi 264

 

50,047,159 

 

6,996,169 

 

3,612,541 2,361,800 

 

344,286 0.047 0.338 0.466 0.212

Missouri 2002

 

316,835,176 

 

51,755,764 

 

26,570,583 22,127,310 

 

2,856,061 0.070 0.428 0.588 0.281

Montana 1576

 

366,870,705 

 

61,557,338 

 

32,232,611 31,257,386 

 

40,251,597 0.085 0.508 0.577 0.304

Nebraska 2143

 

456,245,644 

 

72,030,851 

 

37,903,555 30,116,299 

 

16,954,149 0.066 0.418 0.600 0.269

Nevada 129

 

573,335,271 

 

156,591,574 

 

76,932,282 72,882,827 

 

55,397,634 0.127 0.465 0.662 0.387

New 

Hampshire 4

 

403,218 

 

42,711 

 

21,783 9,259 

 

954 0.023 0.217 0.800 0.300

New Jersey 12

 

714,317 

 

89,710 

 

45,754 53,827 

 

1,587 0.075 0.600 0.533 0.118

New Mexico 468

 

575,246,566 

 

149,583,593 

 

81,147,732 76,437,986 

 

49,347,821 0.133 0.511 0.684 0.341

New York 357

 

98,812,977 

 

9,822,639 

 

5,032,006 7,674,716 

 

286,266 0.078 0.781 0.619 0.342

North 

Carolina 785

 

55,517,863 

 

6,605,368 

 

3,375,328 3,245,691 

 

418,602 0.058 0.491 0.632 0.340

North 

Dakota 1886

 

595,669,875 

 

103,655,250 

 

54,329,685 58,293,602 

 

26,658,263 0.098 0.562 0.703 0.347

Ohio 272

 

25,777,443 

 

2,946,199 

 

1,499,649 1,796,923 

 

73,610 0.070 0.610 0.581 0.241

Oklahoma 1722

 

485,862,434 

 

95,106,374 

 

50,066,159 49,853,489 

 

15,617,471 0.103 0.524 0.770 0.370

Oregon 220

 

301,820,585 

 

68,699,090 

 

36,749,133 40,730,571 

 

15,254,536 0.135 0.593 0.559 0.328

Pennsylvani

a 913

 

191,758,209 

 

19,967,863 

 

10,226,951 13,608,813 

 

511,731 0.071 0.682 0.719 0.362
9 

County Loss Loss Pol Indem

Unit 

Indem

Year Years Liability Premium Subsidy Indem Acres Cost Ratio Rate Rate

Rhode 

Island 10

 

215,001 

 

21,311 

 

11,876 7,703 

 

579 0.036 0.361 0.600 0.172

South 

Carolina 333

 

33,921,655 

 

4,246,845 

 

2,220,294 2,231,155 

 

179,953 0.066 0.525 0.656 0.375

South 

Dakota 1573

 

687,908,605 

 

127,360,448 

 

65,947,643 59,381,576 

 

20,381,212 0.086 0.466 0.552 0.270

Tennessee 490

 

132,060,671 

 

17,174,022 

 

8,751,398 6,243,484 

 

718,369 0.047 0.364 0.555 0.225

Texas 10035

 

5,697,665,157 

 

1,291,001,051 

 

712,751,698 982,790,020 

 

344,971,712 0.172 0.761 0.865 0.419

Utah 194

 

216,710,968 

 

50,278,324 

 

26,116,051 24,455,361 

 

29,123,019 0.113 0.486 0.489 0.253

Vermont 7

 

1,339,082 

 

123,287 

 

62,881 72,592 

 

4,052 0.054 0.589 1.000 0.407

Virginia 893

 

67,689,986 

 

7,678,783 

 

3,975,355 3,893,933 

 

665,363 0.058 0.507 0.650 0.370

Washington 121

 

83,224,605 

 

20,720,353 

 

10,621,276 15,954,430 

 

2,472,433 0.192 0.770 0.519 0.286

West 

Virginia 30

 

1,012,383 

 

111,045 

 

56,164 35,023 

 

7,682 0.035 0.315 0.514 0.221

Wisconsin 747

 

117,745,821 

 

14,473,120 

 

7,782,840 4,381,314 

 

433,469 0.037 0.303 0.441 0.299

Wyoming 264

 

219,953,040 

 

40,166,981 

 

20,108,822 21,694,547 

 

18,349,816 0.099 0.540 0.555 0.262
10

The summaries also make clear another point. The rate of indemnification (claims 

frequency) is very high for the PRF plan. The results indicate that 70-90 percent of policies 

had a claim. Likewise, about 30-60 percent of individual units had a claim. The acreage 

insured under the PRF plan is illustrated in Figure 1-4 below. The figure demonstrates the 

fact that much of the participation is concentrated in the western half of the US. This 

partially reflects the trend toward much larger counties in this section of the country. 

However, even in light of this fact, participation reflects spatial heterogeneity. Figures 1-5 

and 1-6 illustrate the average loss ratio and loss cost ratio. Loss ratios are the highest in 

Texas and southern Florida. 

The relatively high cost of the program, as reflected in the loss cost ratio, is much higher in 

the far west and southwest. Texas appears to have high participation, high loss ratios, and 

high loss cost ratios. In Figures 1-7 and 1-8, we illustrate spatial patterns of claims 

frequency, as measured by the proportions of policies and units triggering indemnities. For 

the sake of comparison, we also illustrate claims frequency using the same metrics for all 

insured crops and all insurance plans. As we have noted, the frequency of claims for PRF 

appears to be far above the claims frequency for all plans and crops. Though geographic 

patterns of claims are similar for PRF and other plans, the rate of claims is much greater in 

the case of PRF.

This suggests that a tangible revision to improve the PRF plan of insurance is to undertake 

actions to reduce the frequency of claims while still providing growers meaningful coverage. 

Several different approaches to changes, including disappearing deductibles and double 

triggers, should be contemplated. A simple approach to modifying coverage to reduce claims 

while still providing protection when conditions are poor is to modify the terms of coverage 

by adopting differing thresholds for triggering a claim and modifying the indemnity payout 

in the event of a claim. A transparent approach to deriving the appropriate rating structure 

for such a change already exists in RMA’s current rating procedures. If we decompose the 

determinants of the raw rate into its two components---the probability of a claim (risk) and 

the expected indemnity payment in the event of a claim, rates can be determined for any 

threshold of coverage. 

Consider a hypothetical example of a unit with 70 percent and 90 percent premium rates of 

0.10 and 0.27, respectively. Any rate can be decomposed as the product of the probability of 

a claim and the conditional expected claim (i.e. Rate= Prob(Claim) x E(Claim|Claim>0). 

These two components can be considered separately to determine a rate for a policy that pays 

90 percent indemnities, but only if losses exceed 70 percent. Continuing the hypothetical 

case, consider such a policy. If the probabilities of loss for the 70 percent and 90 percent

plans are 0.25 and 0.45, a rate for coverage that pays 90 percent but only if losses exceed 70 

percent, would have a rate of only 0.15. Claims frequency would be reduced to a long-run 
11

average of 25 percent and producers would retain protection against catastrophic losses. We 

recommend that RMA consider such coverage, either as an option or as a replacement for the 

current plan. 

Figure 1-4
12

Figure 1-5
13

Figure 1-6

Figure 1-7

Figure 1-8
14

Figure 1-9 

Figure 1-10
15

It is also relevant to note that many areas where the PRF coverage is offered are so dry as to 

likely preclude the long-run establishment of viable pasture and rangeland. Figures 1-11 and 

1-12 below illustrate the long-run averages of temperature and rainfall in the US, calculated 

over the 1990-2019 period. Figure 1-13 presents 2018 premium rates for policies sold at the 

90 percent coverage level. Clear patterns of heat and moisture deficiency stresses are 

apparent in the diagrams. Likewise, the areas that have the highest risk, highest premium 

rates, and highest claims frequency are largely the same. A relevant question for RMA 

pertains to whether coverage should even be offered in these very high-risk (excessively hot 

and dry) areas, which are unlikely to be viable for long-run pasture and rangeland. We 

recommend that RMA consider eliminating coverage in areas where the climate is not 

conducive to viable pasture and rangeland. Such areas may be identified through a 

consideration of the relevant research on the relationship between grassland and precipitation 

and the long-run trends illustrated in the figures. 

Figure 1-11 

Long-Run (1990-2019 Average) Temperature
16

Figure 1-12

Long-Run (1990-2019 Average) Precipitation
17

Figure 1-13 

Pasture and Rangeland Production Systems

Production systems for pasture and rangeland differ widely and the PRF is asked to 

serve the needs of these varied production systems. Perhaps the broadest distinction 

falls along the line of pasture versus rangeland. Sanders, Jolley, and Dobrowolski 

(Figure 1-14) roughly divided the country north to south along the 99th and then the 97th

parallel. Roughly, to the east of this line, there are improved pastures in an area of 

greater rainfall. To the west, there are generally more native forages produced with 

lower rainfall. 
18

Figure 1-14

The USDA NRI Report (2018) provides a useful definition of terms relevant to pasture 

rangeland and cropland. That provides a distinction of the production systems where the PRF 

product is used. 
19

The 2015 NRI also provides data about the relative percentages of U.S. land covers. Figure 1-

15 shows the Federal Lands, Rangeland, and Forest land all three account for 21 percent of U.S. 

land cover (We note some federal lands are used for grazing.). Cropland is slightly behind the 

top three categories at 19 percent of land cover. Relevant to this study is pastureland 

representing 6 percent on land cover. Summed pastureland and rangeland represent more than 

a quarter of all land cover in the U.S. grazed Federal lands 

NRI Definitions

Rangeland

A broad land cover/use category on which the climax or potential plant cover is 

composed principally of native grasses, grass-like plants, forbs or shrubs suitable for 

grazing and browsing, and introduced forage species that are managed like rangeland. 

This would include areas where introduced hardy and persistent grasses, such as crested 

wheatgrass, are planted and such practices as deferred grazing, burning, chaining, and 

rotational grazing are used, with little or no chemicals or fertilizer being applied. 

Grasslands, savannas, many wetlands, some deserts, and tundra are considered 

rangeland. Certain communities of low forbs and shrubs, such as mesquite, chaparral, 

mountain shrub, and pinyon-juniper, are also included as rangeland. 

Pastureland

A land cover/use category of land managed primarily for the production of introduced 

forage plants for livestock grazing. Pastureland cover may consist of a single species in a 

pure stand, a grass mixture, or a grass-legume mixture. Management usually consists of 

cultural treatments: fertilization, weed control, reseeding, renovation, and control of 

grazing. 

Cropland

A land cover/use category that includes areas used for the production of adapted crops 

for harvest. Two subcategories of cropland are recognized: cultivated and non-cultivated. 

Cultivated land comprises land in row crops or close-grown crops, as well as other 

cultivated cropland; for example, hayland or pastureland that is in a rotation with row or 

close-grown crops. Non-cultivated cropland includes permanent hayland and 

horticultural cropland 

Source: USDA Summary Report: 2015 National Resources Inventory (2018)
20

Figure 1-15

A further examination of the forage production systems shows a wide variation in management 

intensity of forage species and factors such as haying versus grazing. Sprinkle (2004) discuss 

the management side of understanding the carrying capacity of forage and also understanding 

the variation in forage demand resulting from differing age and species of the animals to be fed. 

Producers generally deal with the challenge of having sufficient forage for year-round use while 

there is often strong seasonality in forage production. A few strategies used to maintain forage 

across seasons include harvesting hay, planting forage varieties with different growing seasons, 

and extending production by rotations and stockpiling forage. Reeves et al. (2015) discuss new 

tools using weather forecast models to predict growing season forage production to better 

manage production. 

The seasonality of production is directly related to the risk protection needed from the PRF 

product. Table 1-2 is from the USDA NRCS Range and Forage Handbook (2017). It reflects 
21

varieties and management systems typical of the eastern U.S. In several cases production is 

concentrated in a few months that leads to specific rainfall needs to produce that crop. With 

other species or blends, production is more spread out, but major production of these forages 

are primarily found in the April through November period. Herbel (2015) focuses on west 

Texas, Oklahoma, and New Mexico and finds that 70 percent of rainfall in the region falls in 

the spring to summer months making them a critical period for risk protection. Pieper survey 

the literature for the Central Plains and May-June rains or in another region early summer rains 

were highly predictive of forage production. 

Various systems have been attempted to achieve a more nearly year-round production system. 

In colder climates, this tends to involve stockpiling un harvested forage (May et al. 2003). In 

Southern areas with warmer winter temperatures, annual grasses are sometimes overseeded to 

produce winter forage, but interestingly tend to face a problem of too much rather than too little 

rainfall. In drier climates, a wider forage production system is often attempted with irrigation 

ensuring sufficient water. However, various limitations such as the natural growth cycle of 

forages often come into play. 
22

Table 1-2 

Chapter 1 References

U.S. Department of Agriculture. 2018. Summary Report: 2015 National Resources Inventory, Natural Resources Conservation Service, Washington, DC, and Center for Survey Statistics and 

Methodology, Iowa State University, Ames, Iowa. 

http://www.nrcs.usda.gov/technical/nri/15summary

U.S. Department of Agriculture. 2017. NRCS National Range and Pasture Handbook 

(Chapter 5), Natural Resources Conservation Service, Washington, DC, https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1043064.pdf 

Herbel, C.H. (1979). Utilization of grass-and shrublands of the south-western United States. In 

Developments in Agricultural and Managed Forest Ecology (Vol. 7, pp. 161-203). Elsevier. 

May, G., Russell, J. R., Janovick, N. A., Lawrence, J. D., Strohbehn, D. R., & Morrical, D. G. 

(2003). An economic comparison of year-round vs conventional grazing systems in Iowa (No. 

10178). Iowa State University, Department of Economics. 
23

Pieper, R. D. (2005). Grasslands of central North America. Grasslands of the world. Food and 

Agricultural Organization of the United Nations, Rome, Italy, 221-263. 

Reeves, J.L.; J. D. Derner, M.A. Sanderson, S.L. Kronberg, J.R. Hendrickson, L.T. Vermeire,

M.K. Petersen, and J. G. Irisarri, “Seasonal Weather-Related Decision Making for Cattle 

Production in the Northern Great Plains.

https://www.ars.usda.gov/ARSUserFiles/1354/8.%20Reeves%20et%20al.%202015%20Rangel

ands.pdf 

Sanders, M.A. L. A. Jolley, and J.P. Dobrowolski (2012), “Pastureland and Hayland in the 

USA: Land Resources, Conservation Practices, and Ecosystem Services,

https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/16/stelprdb1080492.pdf

Sprinkle, J. (2004). How Many Animals Can I Graze on My Pasture? 

https://repository.arizona.edu/bitstream/handle/10150/144711/az1352-2004.pdf?sequence=1
24

Chapter 2 Task 1: A comprehensive review of the County Base Values 

The County Base Value in the PRF insurance product essentially represents the value of 

insurance per acre insured. The CBV is a base measure from which insureds can adjust insurance 

coverage amount and allocate it across the chosen intervals. Multiplying the coverage level 

chosen and the productivity factor to the CBV gives the dollar protection (e.g., liability amount) 

for the insured’s PRF insurance contract. In this section, we describe the CBV calculation 

methodology as it is currently implemented, analyze the insurable risks present with lack of 

precipitation (depending on intended use), evaluate the current CBV methodology, and provide 

recommendations to improve the CBV calculation approach. 

Current CBV Methodology (2020)

Over the last four years (2016-2019), there have been several changes made to the methodology 

for calculating the CBVs to improve the accuracy of this measure. The history of these changes 

is discussed in the RMA document titled: “Pasture, Rangeland, and Forage County Base Values 

Method” (RMA, 2019). The PRF insurance product insures pasture, rangeland, and forage 

intended for haying and grazing. Moreover, the haying practice is separated into two distinct 

types: non-irrigated haying and irrigated haying. Therefore, there are three different CBV 

calculation methodologies for each insurable intended use: non-irrigated haying, irrigated 

haying, and grazing. The CBV methodology for each intended use is discussed in turn below. 

The summary of CBV calculation steps is provided in the Appendix. 

Non-irrigated Haying CBV

The CBV for non-irrigated haying practice is based on the expected annual revenue from an acre 

of non-irrigated hay production. That is, CBV = non-irrigated hay yield × non-irrigated hay 

price. The concept is such that this represents the total value of insurable non-irrigated hay 

production that could be lost (due to, say, lack of rainfall). In the context of the PRF insurance 

product, it would have been ideal if CBV values are calculated for each insurable grid 

(encompassing all intervals) available for the product. However, the main problem is that limited 

data exists for the yield and price components of the simple CBV calculation above (e.g., for 

non-irrigated hay revenue) at the ideal level of aggregation desired. Hence, the PRF insurance 

product has a CBV calculation procedure giving values at the “agricultural district” (sub-state) 

level based on available data and information at different levels of aggregation (e.g., state and 

county-level datasets are utilized to calculate the agricultural-district-level CBV for non-irrigated 

hay production). 

The non-irrigated hay yield component (in tons/acre) of the CBV is calculated by first taking the 
25

10-year average of state-level NASS yield data (e.g., NASS “all hay” yields in tons/acre) for 

each state that PRF is available. Then, a non-irrigated haying ‘factor’ is calculated based on the 

ratio of non-irrigated yield relative to the “all hay” yields based on information from the NASS 

Farm and Ranch Irrigation Survey (FRIS). This ‘factor’ is then multiplied to the 10-year state 

average ‘all hay’ yields to get an estimate of the non-irrigated hay yield for each state (in 

tons/acre). The non-irrigated haying ‘factor’ serves to adjust the average state-level “all hay” 

yields so that it will coincide more with non-irrigated hay production (i.e., rather than a hay yield 

that represents a mixture of both irrigated and non-irrigated production). To calculate an 

agricultural-district-level non-irrigated hay yield, the NRCS hybrid productivity model (HPM) is 

then utilized to estimate a percent difference between district-level and state-level net primary 

productivity (NPP) measures (e.g., we call this the NPP district-state factor). This NPP “districtstate” factor is multiplied to the state-level non-irrigated hay yield estimate to get the 

agricultural-district-level non-irrigated hay yield value (in tons/acre). 

On the other hand, the non-irrigated hay price component of the CBV calculation is based on 

three-year average state-level hay price data (in $/ton) from NASS (e.g., the NASS “all hay, 

excluding alfalfa” price data). This is the non-irrigated hay price procedure used for all PRF 

states, except for CO, ID, NV, NM, OR, and WA. For these exceptions, the reported NASS hay 

prices for these states mostly reflect the irrigated practice (and is valued higher). Thus, for these 

exception states, a regional average of the state-level non-irrigated hay price (in $/ton) in the 

Plains states is used instead. 

The average state-level non-irrigated hay price ($/ton) is then multiplied by the agriculturaldistrict-level non-irrigated hay yield value (ton/acre) to eventually get the district-level nonirrigated haying CBV (in $/acre) used in the PRF insurance product. Several other capping 

procedures are then conducted, such as limiting year-to-year CBV changes to +/-35 percent and 

having a maximum CBV value of $500. 

Irrigated Haying CBV

In contrast to the non-irrigated haying CBV that is mainly based on an estimate of expected 

revenue, the irrigated haying CBV calculation method is primarily based on the cost of 

additional irrigation. The concept is that lack of precipitation (or rainfall) in an irrigated 

perennial PRF production context will generally mean that the irrigator will need to pump more 

water to compensate for the shortfall in precipitation. Hence, the “loss” incurred due to the lack 

of rainfall is the additional cost of pumping water. 

Therefore, irrigated haying CBV is primarily based on information from the FRIS survey that 

reports irrigation costs per acre-inch by source (at the state-level). A weighted average of the 

irrigation costs from all sources is calculated at the state-level to estimate an overall average 
26

state-level irrigation cost per acre-inch. Adjustments to these overall state-level irrigation costs 

are then implemented for Kansas and Texas based on well-depth data collected from an irrigation 

model (e.g., we interpret this to mean that costs go up as well-depth increases in these states). No 

further adjustments are made for other PRF states. The estimated state-level irrigation cost per 

acre-inch in each state is then multiplied with rainfall levels (in inches) to get the irrigated haying 

CBV ($/acre) estimate. The irrigated haying CBVs are then capped at 75 percent of the nonirrigated CBV. 

Grazing CBV

Much like the non-irrigated haying CBV, the grazing CBV is conceptually based on an expected 

hay revenue measure. The idea is that the impact of precipitation shortfalls for grazers is 

typically the cost of supplemental hay feeding due to the forage production lost in the field with 

the lack of rainfall. However, the procedure used to calculate the hay yield and the hay price 

components of the expected revenue measure for grazing CBV is different from the non-irrigated 

haying CBV. This is partly because hay yield for grazing can be more directly approximated 

using information about animal stocking rates and the forage consumed per animal unit. Also, 

hay yields intended for grazing tend to be lower (on average) relative to hay yields that are 

harvested for hay. The price of hay for grazing also is typically lower than the price of harvested 

non-irrigated hay since the harvested hay prices implicitly incorporate the higher cost of 

producing or maintaining pasture for haying. Pasture grass for grazing also tends to have lowerquality relative to an equivalent harvested baled hay value, which may again result in the price 

differential. 

The grazing hay yield component of the grazing CBV is calculated based on NASS state-level 

pasture rental rate and grazing rate information. Yearly state-level pasture rental rates from 

NASS are measured on a dollar per acre basis, and the grazing rate (also called grazing fee) is 

measured in dollars per animal unit month (AUM). To get a ton/acre grazing hay yield value, 

first, a 10-year state-level average of pasture rates and grazing rates is calculated for each state 

where data is available. Second, the 10-year average pasture rate (in $/acre) is then divided by 

the 10-year average grazing fee (in $/AUM). This ratio provides an estimate of average forage 

consumption measured in AUMs per acre (e.g., this is an estimate of the amount of forage 

“harvested” by the livestock). Since an AUM is equivalent to about 0.47 tons of hay (based on 

NRCS data), the last step is to multiply 10-year state-level average forage consumption (in 

AUMs/acre) by the 0.47 tons/AUM to get an estimate of the 10-year state-level average grazing 

hay yield (in tons/acre). This is the estimate of the grazing hay yield component of the expected 

revenue.

The price component of the grazing CBV is estimated by utilizing a “blended” measure derived 

from state-level grazing rate information and non-irrigated hay price information. The grazing 
27

hay price estimates are based on three-year state averages of the grazing rates and non-irrigated

hay prices. First, three-year averages of the state-level grazing rate data (in $/AUM) and the 

state-level non-irrigated hay price data (in $/ton) are calculated. Second, the three-year average 

state-level grazing rate is then divided by the 0.47 tons/AUM factor (as mentioned above). Recall 

that this latter factor represents the “ton” equivalent of the “AUM” measure of forage 

“harvested” by the livestock. The resulting value from this second step is an estimate of the 

grazing rate in the desired dollars per ton ($/ton). The last step is calculating the “blended” 

grazing price (in $/ton) by taking the average of the grazing rate ($/ton) calculated in the second 

step and the non-irrigated hay price ($/ton). The pricing procedure described above applies only 

to states with grazing rate information in ($/AUM). For states without grazing rate information, 

the state-level non-irrigated hay price is simply multiplied with a 0.762 factor, where this factor 

represents the ratio of grazing rates to non-irrigated hay price in the Plains states. 

An initial estimate of the grazing CBV at the state-level (in $/acre) is then calculated by 

multiplying the grazing hay yield estimate (in tons/acre) with the “blended” grazing price 

estimate (in $/ton). County-level grazing CBVs are then derived from the state-level grazing 

CBV using the pasture productivity estimates from the NRCS HPM (as described in the nonirrigated hay CBV section above). County-level productivity measures are estimated for each 

county in a particular state, and then these county-level measures are divided by the state-level 

productivity measure to get the “county-state” productivity factor (e.g., the ratio of the county 

and state productivities). The “county-state” productivity factor is then multiplied by the statelevel grazing CBV estimate to compute a county-level CBV (in $/acre). The county-level CBVs 

for all counties that comprise each agricultural district in a state are then averaged to get the 

district-level grazing CBV (in $/acre) that is used for the PRF insurance product. 

Rangeland and Pastureland CBV differences

To follow on the previous section, we want to delve further into the differences between 

pastureland and rangeland CBV. In Chapter 1 of this report, NRI definitions of “rangeland” and 

“pastureland” were discussed to distinguish one from the other. For rangelands, one key 

identifying characteristic is that rangelands used for grazing typically have “little or no chemicals 

or fertilizer being applied.” In contrast, pastureland used for grazing involves management 

practices that “usually consists of cultural treatments: fertilization, weed control, reseeding, 

renovation...” With these distinguishing characteristics, it is natural to expect that the 

productivity of pastureland used for grazing would be higher than rangelands for grazing since 

productivity-enhancing management practices are implemented in pastureland while it is not 

applied in rangelands. Consequently, CBV values may also then be higher for pastureland used 

for grazing vis-à-vis rangelands used for grazing (which would justify an adjustment factor in the 

grazing yield component of the grazing CBV calculation). 

Using high-resolution remote sensing and satellite data sets, the study of Robinson et al. (2019) 

supports the existence of a productivity differential between pasturelands (that are managed) and 
28

rangelands (that are not managed). In Robinson et al. (2019), managed or improved pastureland 

are characterized as “private” lands where private owners actively manage their pasture through 

fertilization, reseeding, etc. On the other hand, what we call unmanaged rangeland in this report 

coincides with what Robinson et al. (2019) call “public” lands (with no or little management). In 

general, Robinson et al. (2019) find that the productivity of private grazing land is consistently 

higher than public lands. Considering the whole continental US (CONUS), productivity of public 

lands is about 48% of the productivity of private lands (See Figure 4 and supplemental Table S1 

in Robinson et al., 2019). For the Western States (Washington, Oregon, California, Idaho, 

Nevada, Arizona, New Mexico, Utah, Colorado, Wyoming, and Montana), productivity of public 

grazing lands is 59% of the productivity of private grazing lands. These results strongly suggest 

that managed private lands (or pasturelands) for grazing are more productive than unmanaged 

public lands (or rangelands).1

An online resource from Michigan State University (Lindquist, 2014) also provides evidence that 

grazing land with no nitrogen (N) fertilization tends to be less productive than any grazing land 

with N application (i.e., one-time spring N application or split N applications). Based on several 

field trial data sets in Michigan (as reported in Lindquist 2014), the calculated ratio between the 

average forage yields in “no-N fertilization” lands and the “N-managed” lands ranged from 45% 

to 91% (with an average ratio of about 65%). Overall, these trial data results (ranging from 1966-

2014) support the idea that unmanaged rangelands (without any N fertilization) are less 

productive than managed pasturelands (with N fertilization). 

Baldwin, Hakinson, and Anderson (1974) found that a single application of 27-12-O fertilizer on 

native rangeland in northwestern Oregon produced a 4-year total herbage production of 2.66 

times as much as on unfertilized plots produced. Higher levels of fertilizer increased the ratio. 

Increasing the rate of fertilization improved the strength of perennial grasses, increased 

utilization of herbage by cattle, and extended the forage season. Goetz (1969) found 67 pounds 

of nitrogen per acre increased rangeland forage production in North Dakota by 63 percent 

relative to no nitrogen application. Mosely, Brewer, and Skeen (2020) recommend stocking 

rates on healthy rangeland to be around 1⁄2 that of well-managed seeded pastures in Montana. 

We also note that Hooper and Johnson (1999) conducted regression analysis examining the 

degree to which water and nitrogen limit dryland forage production systems. One conclusion 

they reach is that the relative increase in forage production due to nitrogen application is robust 

across different rainfall scenarios. 

Observations, Analysis, and Recommendations

Overall, we find the CBV calculation methods used for each intended use covered in the PRF 

insurance contract (e.g., non-irrigated hay, irrigated hay, and grazing) to be appropriate. We 

believe that the conceptual basis for the CBV values are sound. As a risk management tool, the 

1 Note that the Robinson et al (2019) also provided a supplemental data set that includes information about the 

proportion of private vs. public grazing land by State (as well as the corresponding average productivity for each 

type of grazing land by State). 
29

PRF insurance aims to compensate hay producers and grazers for the value of production lost in 

their pasture (or rangeland) when there are shortfalls in precipitation (i.e., given that rainfall, or 

water in general, is a major determinant of eventual pasture/rangeland/forage production). 

Hence, the CBV should reflect the total value at risk (i.e., ‘the insurable risk’ or the total value of 

production that can be lost) when there is effectively no rainfall (or zero pasture production). 

For the case of non-irrigated hay production and/or pasture intended for grazing, having the 

CBVs for these intended uses conceptually linked to an expected revenue measure is reasonable. 

This is because expected revenue (hay yield multiplied by hay price) is generally the value of the 

hay lost (in $/acre) when there is a lack of sufficient rainfall. On the other hand, for irrigated hay, 

the ‘loss’ or additional cost incurred when there is a lack of rainfall is normally the additional 

cost of pumping more water to compensate for the shortfalls in precipitation. Hence, the irrigated 

hay CBV being conceptually linked to an estimate of pumping cost seems reasonable as well. 

These underlying conceptual linkages indicate that the CBV calculation methods are reasonably 

linked to the major insurable risks PRF purchasers face for each intended use when there is 

insufficient rainfall. 

Given the general conceptual soundness of the CBV calculation methods for each intended use, 

the main challenge for RMA is to precisely estimate the CBVs given the inherent limitations of 

the data available for calculating it (e.g., limitations of data on the non-irrigated hay and grazing 

hay yields and prices, and the irrigation pumping costs). Hence, the remainder of this section 

discusses observations and recommendations concerning further improving the accuracy of CBV 

calculation methods and making adjustments to other PRF contract elements given the 

improvements in the CBV. In general, we believe that the modifications to the CBV calculation 

methods implemented by RMA over the last four years have already improved CBV estimates, 

and the suggestions here are meant to refine the CBV process further. 

Setting a minimum grazing CBV: County-level NASS pasture rental rate data

Currently, there is no set minimum value for the district-level grazing CBVs used in the PRF 

contract. Therefore, it is possible for the district-level grazing CBV (used for a particular county) 

to be lower than the estimated NASS county-level pasture rental rate. Newton (2018), for 

example, has shown that there are cases in South Dakota where 2019 CBVs were up to 46 

percent lower than NASS state-level pastureland rent in 2018. Though it should be noted that, in 

2020, RMA was able to raise CBVs in South Dakota in response to this issue. There were also 

about 225 counties with 2019 CBVs below the 2017 NASS county-level cash pastureland rent 

(though there were over 1000 counties with CBVs more than 200 percent higher). Hence, 

Newton (2018) argues that in counties where grazing CBVs are below county-level pastureland 

rents, the PRF indemnity payments for a full loss will not be enough to cover the minimum cost 

associated with accessing forage for supplemental feeding (e.g., say if they want to rent nearby 
30

pastureland for supplemental feeding of their livestock). Pastureland rents seem to be a 

justifiable minimum value for the grazing intended use. 

Given these arguments, it seems reasonable for RMA to at least explore whether it is feasible to 

apply a minimum CBV value that is equal to a county-level or state-level measure of pastureland 

cash rent (perhaps in a previous year or based on historical average). There is a lag in the 

availability of NASS county-level and state-level pastureland rental data, which may limit the 

feasibility of applying a minimum value. However, a one-year lagged pastureland rent value 

from NASS (at the county- or state-level) as a minimum bound would still be reasonable (in our 

opinion). Applying this minimum (in conjunction with the other changes recommended in this 

report) may improve the risk mitigation benefits from the PRF product. 

Validating the HPM productivity factors against an alternative model

In the current CBV methodology, HPM-derived productivity factors are utilized in the nonirrigated haying and the grazing CBV calculations. In particular, a “district-state” productivity 

factor is used for calculating the non-irrigated haying CBV, and a “county-state” productivity 

factor is used for computing the grazing CBV. These factors were derived based on the NRCS 

HPM model so that estimates of the district-level non-irrigated haying CBV and the county-level 

grazing CBV are consistent with the inherent “productivity” of the pasture at these levels of 

geographic aggregation. The use of these productivity factors somewhat assures that the 

estimated CBVs at these levels are consistent with the inherent capacity of the land to produce 

pasture in these areas. 

Aside from the NRCS HPM, Williams and Travis (2019) have used the U.S. Forest Service’s 

“Rangeland Vegetation Simulator” (RVS) in their study that evaluates PRF weather index 

products using alternative drought indices instead of a rainfall index. Reeves (2016) more fully 

describes how the RVS works. Williams and Travis (2019, p. 633) describe the RVS as follows: 

“The RVS calculates annual rangeland production for the western and central United States by 

combining normalized difference vegetation index (NDVI) values with precipitation data and 

site-specific biophysical settings (Reeves 2016). The RVS is validated with direct measurements 

of rangeland production values from the National Resource Conservation Service Soil Survey 

Geographic dataset (SSURGO; Reeves 2016). RVS data are consistent from year to year and are 

available from 1984 to present, thus providing the most comprehensive assessment of rangeland 

productivity in the United States.” Given the above description of RVS, it seems that output from 

this model can serve as an alternative data source to at least validate the productivity values 

generated from the NRCS HPM. Comparisons of the resulting CBV values from the RVS vis-àvis the NRCS HPM can be conducted to see if there are any large discrepancies in the estimates. 

In the end, exploring an alternative source for productivity values can help improve the 

robustness of the CBV estimates. 
31

Minor clarifications to the irrigated hay CBV and the grazing CBV procedure

One issue with the irrigated CBV is the conceptual question of whether the irrigation cost should 

be multiplied by the average rainfall level to get the irrigated hay CBV, or is it more appropriate 

to multiply the irrigation cost by an estimate of the average amount of water pumped historically 

(in inches) in the geographical area of interest. It seems that the ‘insurable risk’ associated with 

irrigated hay should be tied more to the actual average water used rather than the average rainfall 

level. Multiplying based on expected rainfall is from the notion that an irrigated producer will 

irrigate more than normal to make up for a shortfall from expected rainfall, which is why the 

CBV is set based on expected rainfall. For example, in a high rainfall area (e.g., 30 inches per 

year), a producer would only pump an additional 4 inches. However, in a drought year, they may 

pump 14 inches. For a more moderate average rainfall area (say 10 inches per year), a producer 

may routinely irrigate for an additional 35 inches, but the irrigated CBV only covers the 10 

inches per year average. The logic above makes sense though it seems that in this example the 

irrigated CBV tends to overinsure irrigated areas with higher average levels of rainfall (e.g., the 

30 inches of rain example), and underinsure irrigated areas with lower average levels of rainfall. 

As mentioned above, all we are suggesting here is to simply re-evaluate this step. Or perhaps 

base it on the historical “additional” pumping in severe drought events at minimum rainfall 

levels (i.e., the observed pumping in severe drought years relative to the “normal” pumping in 

“normal” rainfall years). Our point here is for RMA to simply evaluate further whether it is 

better to use average rainfall or some other “water quantity” to calculate the irrigated hay CBV. 

In addition, we note here that there is inconsistency in the non-irrigated hay CBV procedures 

relative to the grazing hay CBV procedure in terms of going from the state-level estimates to the 

final district-level estimates. In the non-irrigated haying CBV, the state-level non-irrigated hay 

yield was converted directly to a district-level yield estimate using the “district-state” conversion 

factor (derived from the NRCS HPM). Then, the district yields are multiplied with the state-level 

price estimates to get a non-irrigated CBV at the district level. On the other hand, for the grazing 

CBV, the state-level grazing yields and state-level “blended” grazing prices are first multiplied to 

get an initial state-level grazing CBV. A “county-state” conversion factor (also from NRCS 

HPM) is used to convert this estimate to a county-level CBV and then an average across counties 

within a district is used to generate a district-level CBV. For consistency in procedures, we 

suggest that the “conversion methods” used to derive a district-level CBV for non-irrigated hay 

and grazing be made consistent with each other. Perhaps the decision on which conversion 

procedure to use for both non-irrigated haying and grazing will depend on which “conversion 

factor” is deemed more accurate (either the district-state or county-state). Note that the “factor” 

used in calculating the non-irrigated hay CBV is a “district-state” factor, while for the grazing 

CBV it is a “county-state” factor. In addition, for the grazing CBV, the county-level CBVs are 

aggregated up to the district-level (using county area as weights) to get a district-level grazing 
32

CBV. This aggregation was not undertaken in the non-irrigated hay CBV. The difference in the 

“factors” used and the aggregation step for the grazing CBV would likely matter in this case. 

Nonetheless, our point is to simply re-evaluate these steps and perhaps make the calculations for 

non-irrigated haying CBV and grazing CBV more consistent with each other. One approach to 

make both calculations consistent is to use the same “district-state” factor in the yield calculation 

step of the grazing CBV calculation procedure. Alternatively, the “county-state” factor (plus 

aggregation to the district) can be used in the last few steps of the non-irrigated haying CBV 

calculation. The choice depends on which “factor” is more reliable and accurate.

Adjusting the productivity factor limits given the CBV calculation improvements? 

The PRF insurance contract includes an option where producers can choose a “productivity 

factor” (PF) between 0.60 and 1.50, which enables them to adjust the CBV up or down to make 

it more commensurate with their circumstances. This provides some flexibility to adjust the 

insurable value (i.e., insured liability) since the CBV value is estimated at a higher geographical 

aggregation (e.g., at the agricultural-district-level for grazing CBV), which does not necessarily 

coincide with individual farmer CBVs. The productivity factor is largely considered a 

“correction factor” to overcome the inherent limitations of the estimated CBV and allow the 

insureds to adjust the policy CBV estimates to make it coincide with their individual CBV. To 

some degree, it also allows PRF producers to adjust their liability commensurate to their basis 

risk (i.e., make it such a way that basis risk is minimized). For example, insureds can increase 

their individual CBV value if they think productivity (or yield) of their land is higher than the 

productivity (or yield) implied by the more aggregate CBV value offered in the PRF policy (or 

vice-versa). 

However, even if this is the intent behind the productivity factor theoretically, in practice most 

PRF producers simply pick higher PRF levels (e.g., at the state-level, PF averages are often 

above 1.0 and very seldom below; See Agralytica, 2014, p. 110-111).2

 This behavior of picking 

the highest PFs is consistent with maximizing returns to insurance rather than the risk 

minimization objective of the PRF offering (See Goodrich et al. 2019; Cho and Brorsen, 2019).3

A recent USDA-OIG report (USDA-OIG, 2019, p. 10-12) provided examples where insureds 

were able to pick the 150% productivity factor even if the productivity of the land based on 

NRCS data suggests that average productivity/yields in the insured land are substantially lower 

than the implied productivity/yields from the CBV. 

2 Note that the Agralytica (2014) report indicate that agents and producers generally like the flexibility afforded by 

the current PF levels to tailor the coverage to their individual productivities and premiums they are comfortable 

paying. Agralytica (2014) even suggested increasing the PFs above 150% in some locations, given the belief that 

most of the CBV values at that time are inaccurate (and likely underestimated). But it should be noted that CBV 

calculation methodologies have improved since 2014, and are likely more accurate than six years ago.

3 In their analysis, Cho and Brorsen (2019) points out that lower PF choices are more “optimal” in a risk 

minimization framework as compared to an insurance return maximization framework.
33

Nonetheless, with improvements in the CBV calculations over the last five years (that improves 

accuracy and precision) and implementation of the minimum grazing CBV above, we believe 

that it is appropriate to reduce the range of available productivity factors in the PRF insurance 

offering. Similar area-based insurance plans offered by RMA that triggers on a county-yield 

“index”, such as the Area Risk Protection Insurance (ARPI), only have a productivity range 

between 0.8 and 1.2 (as compared to the 0.6 to 1.5 range in PRF). Hence, for consistency across 

index-based RMA product offerings and to align better with risk minimization behavior, we 

suggest narrowing the productivity factor to the 0.8 to 1.2 range. 

If the narrowing of the PRF range is implemented, it is important to monitor the effects and 

performance of the program from this change. First, as in the Agralytica (2014) report, it is 

important to continually examine the productivity choices of insured PRF growers. This analysis 

will give insight into whether it is still the case that most producers pick the higher coverage

levels (around 1.2 or above) and not coverage levels below 0.9 (i.e., suggesting the 

appropriateness of increasing the lower limit to 0.8). Frequent analysis and monitoring of the 

impact of narrowing the productivity factor range on liability, premiums, and indemnity levels 

would also be valuable (especially in conjunction with the other recommendations in this report 

– setting a minimum grazing CBV, lowering coverage levels available, etc.). There may be a 

concern that reducing the maximum PF limit may result in “drastic” increases in insured PRF 

acres. To address this issue, one can monitor and statistically estimate the relationship of PF 

choice and insured acres using the policy-level administrative data. This type of recurring 

analysis can give an insight into whether insured PRF growers increase insured acres when 

picking lower productivity factor levels. Even if RMA data on “insured PRF acres” is not a 

perfect measure of the total acres the producer has access to, the recommended analysis here 

would still provide some inferences of whether farmers that choose low productivity factors to 

increase the PRF acres insured.

Second, for each county where PRF is offered, it would be useful to continually monitor and 

compare the implied yields (or productivity) from the NRCS productivity model or the US Forest 

Service RVS model (or other models) vis-à-vis the yields used in the CBV calculations. In 

particular, the estimated yields used to calculate the non-irrigated haying and grazing CBVs for 

each county compared to the NRCS model yields). This exercise will help determine and avoid 

situations illustrated in the USDA-OIG (2014) report where implied productivity of the insured 

land based on the PRF contract choices of the grower (e.g., 150% productivity factor, etc.) is 

substantially higher than what the NRCS data (or other sources) indicate. In particular, one can 

also determine whether the estimated yields from productivity models are consistent with the 

implied yields used in calculating CBVs (and maintaining program integrity). In conclusion, we 

believe that narrowing the productivity factor range offered in PRF is appropriate at this time, 

and continual monitoring of the effects of this recommendation is advisable. 
34

Main CBV Recommendations

Validating the HPM productivity factors against alternative models 

Recommendation: The U.S. Forest Service’s “Rangeland Vegetation Simulator” can serve as an 

alternative data source to validate the productivity values generated from the NRCS HPM. 

Comparisons of the resulting CBV values from the RVS vis-à-vis the NRCS HPM can be 

conducted to see if there are any large discrepancies in the estimates. In the end, exploring an 

alternative source for productivity values can help improve the robustness of the CBV estimates. 

Modification of the County Based Value (CBV)

Currently, there is no set minimum value for the district-level grazing CBVs used in the PRF 

contract. Therefore, it is possible for the district-level grazing CBV (used for a particular county) 

to be lower than the estimated NASS county-level pasture rental rate. Newton (2018), for 

example, has shown that there are cases in South Dakota where 2019 CBVs were up to 46 

percent lower than NASS state-level pastureland rent in 2018. Based on research cited in our 

exploration of the CBV, we recommend RMA apply a minimum CBV value that is equal to a 

county-level or state-level measure of pastureland cash rent (perhaps in a previous year or 

based on historical average). Applying this minimum (in conjunction with the other changes 

recommended in this report) may improve the risk mitigation benefits from the PRF product. 

We also recommend that the grazing CBV be partitioned to differentiate improved pasture (or 

pastureland) from unmanaged rangeland. To qualify as pastureland, evidence of fertilization 

and/or lime, seeding, weed control, or other pasture improvements would be required to receive 

a higher CBV for pastureland relative to rangeland. A producer would be required to selfcertify that their land is pastureland or rangeland. Verification of pastureland would include 

input records showing “Management” of the land. A distinction between rangeland and 

pastureland CBV would more accurately reflect productivity. Evidence of cultural practices 

such as fertilization, weed control, and reseeding generally result in greater forage production 

and animal carrying capacity. 

The productivity differential estimates from the papers reviewed above (See section above titled 

“Rangeland and Pastureland CBV differences”) indicate that a rangeland-pastureland factor in 

the range of 60%-70% is justifiable as a “conservative” measure (especially in the Western 

States where there is a good mixture of unmanaged rangelands and managed pastureland). 

Hence, the State-level grazing CBV yield estimate can be adjusted downward by 30%-40% for 
35

insureds that self-select and say that their PRF-insured land is unmanaged rangeland.4 On the 

other hand, the State-level grazing CBV yield estimate can be adjusted upward by 30%-40% for 

insured that self-selects and say that their PRF-insured land is managed pastureland. 

 Notwithstanding these recommendations for adjusting the State-level grazing yield in the 

grazing CBV calculations, the recommendation in this report of using a minimum grazing CBV 

value based on pastureland rents should still serve as the “floor” on the calculated CBV. That is, 

if the resulting district-level CBV with the downward adjustment (due to using unmanaged 

rangeland) is lower than the minimum CBV based on pastureland rental rates, then the minimum 

CBV based on pastureland rental rates will be the one that is applicable.

Adjusting the CBV Productivity Range

With improvements in the CB/V calculations over the last five years (that improves accuracy and 

precision) and implementation of the minimum grazing CBV above, we believe that it is 

appropriate to reduce the range of available productivity factors in the PRF insurance offering. 

Similar area-based insurance plans offered by RMA that triggers on a county-yield “index”, such 

as the Area Risk Protection Insurance (ARPI), only have a productivity range between 0.8 and 

1.2 (as compared to the 0.6 to 1.5 range in PRF). Hence, for consistency across index-based 

RMA product offerings and to align better with risk minimization behavior, we suggest 

narrowing the productivity factor to the 0.8 to 1.2 range. 

Chapter 2 References

Agralytica. 2014. “Evaluation of PRF Rainfall Index and Vegetation Index Pilot Crop 

Insurance.” Programs. Final Program Evaluation Summary Report submitted to the RMA (Oct 1, 

2014) 

Baldwin, D. M., Hawkinson, N. W., & Anderson, E. W. (1974). High-rate fertilization of native 

rangeland in Oregon. Rangeland Ecology & Management/Journal of Range Management 

Archives, 27(3), 214-216. 

4 However, note that this downward adjustment may be more appropriate only if the State in question has a 

predominantly higher proportion of pastureland (i.e., the threshold proportion can be set by RMA (say, for example, 

at 51% or at 70%) since the calculated State-level CBV in this case likely represent yields from managed 

pasturelands rather than unmanaged rangelands). The data set in Robinson et al. (2019) can be used to determine the 

proportion of managed pasture (private lands) relative to unmanaged rangeland (public lands) and to set the 

threshold proportion. The same sort of argument can be used for the upward adjustment discussed in this paragraph 

(that is, the upward adjustment will only be applied if the State in question has predominantly more unmanaged

rangelands).
36

Cho, W., and W. Brorsen. (2019). “Evaluation of RI-PRF Crop Insurance Program Design.” 

Selected Paper presented at the SCC-76: Economics and Management of Risk in Agriculture and 

Natural Resources Meeting, Kansas City, MO (April 4-6).

Goetz, H. (1969). Composition and yields of native grassland sites fertilized at different rates of 

nitrogen. Journal of Range Management, 384-390. 

Goodrich, B., Yu, J., & Vandeveer, M. (2019). “Participation patterns of the rainfall index 

insurance for pasture, rangeland, and forage program.” The Geneva Papers on Risk and 

Insurance: Issues and Practice. 45: 29–51. 

Hooper, D. U., & Johnson, L. (1999). Nitrogen limitation in dryland ecosystems: responses to 

geographical and temporal variation in precipitation. Biogeochemistry, 46(1-3), 247-293. 

Linquist, J. (2014). “Evaluating the Economics of Pasture Based Systems for the Beef Cow 

Herd.” Unpublished White paper, Michigan State University.

https://www.canr.msu.edu/uploads/396/ 

60804/Evaluating_the_Economics_of_Pasture_Based_Systems_for_the_Beef_Cow_Herd.pdf.

Accessed June 13, 2020. 

Mosley, Jeff and Tracy Brewer, and Joe Skeen, “Grazing Management for Spring Pastures 

http://animalrangeextension.montana.edu/range/grazing-management/gm-spring-pastures.html 

Accessed June 13, 2020. 

Newton, J. (2018). “Pasture, Rangeland, and Forage... A Potential Solution.” Market Intel 

Article of the American Farm Bureau: https://www.fb.org/market-intel/pasture-rangeland-andforage-a-potential-solution (Last accessed: 2/8/2020) 

Reeves, M. C. (2016). “Development of the Rangeland Vegetation Simulator: A module of the 

Forest Vegetation Simulator.” Joint Fire Science Program Final Rep. for Projects 12-1-02-15 and 

14-S-01-01, 129 pp., https://www.firescience.gov/projects/12-1-02-15/project/12-1-02-

15_final_report.pdf (Last accessed: 2/6/2020). 

RMA (2019). “Pasture, Rangeland, and Forage County Base Values Method.” Unpublished 

manuscript. 

Robinson, N.P, Allred, B.W., Naugle, D.E., Jones, M.O. (2019). “Patterns of rangeland 

productivity and land ownership: Implications for conservation and management.” Ecological 

Applications. 29(3): e01862. 

USDA-OIG. (2019. “Annual Forage Program and Followup on Pasture, Rangeland, and Forage 

Program Recommendations.” USDA-OIG Audit Report 05601-0006-31, Washington, DC (July). 
37

Williams, T.M., Travis, W.R. (2019). “Evaluating Alternative Drought Indicators in a Weather 

Index Insurance Instrument.” Weather, Climate, and Society. 11(July): 629-649. 
38

Chapter 3 Task 2: A review of the methodology used for the PRF rainfall 

index and premium rates. 

Pasture and Rangeland Literature Review

This section of the report provides a review of scientific literature related to the pasture and 

rangeland insurance product. We begin with the origins of index insurance and then the 

rating of index insurance and then demand for index insurance. We conclude with a 

discussion of recent advances in index insurance. 

Origins of index insurance

The scholarly literature on index insurance has grown tremendously over the past 20 years. A 

complete review of that literature would be beyond the scope of this report. Instead, we will 

describe some of the seminal work on index insurance and then review more recent work of 

particular relevance to the PRF insurance product.

Index insurance products can generally be classified into two broad categories: products 

based on indexes that measure aggregate losses over a group (e.g. Area Yield Protection, 

AYP or Area Revenue Protection, ARP) and products based on indexes that are believed to 

be highly correlated with losses (e.g., Pasture, Rangeland and Forage, PRF). With the former 

category, an index of group losses within a defined geographic region serves as a proxy for 

the losses of individual members of the group. The index must be based on data aggregated 

over a large enough scale that an individual policyholder cannot significantly influence the 

realized value of the index and hence, the indemnity. With the latter category, the variable on 

which the index is based (often, a measure of weather events) serves as an indicator or 

predictor of policyholders’ realized losses (Murphy et al., 2011). 

Why would an insurer offer index insurance instead of traditional, loss-based insurance? In 

many respects, traditional insurance is the most straightforward way to offer insurance 

protection because indemnities are based directly on the measurable losses experienced by 

the policyholder. But this direct connection between the loss experienced by the policyholder 

and the indemnity received can also create challenges. In some cases (e.g., pasture and 

forage), it is extremely difficult to measure the actual loss that has occurred. Other 

advantages of index insurance relative to loss-based insurance include less exposure to moral 

hazard and adverse selection and lower operational costs (since there is no need for policyspecific underwriting or on-farm loss adjustment). 

The widely recognized limitation of index insurance products is that policyholders are 

exposed to basis risk. Technically, basis risk is the variance of the conditional distribution of 

the policyholder's losses given a specific value of the index. Since sufficient data are 
39

generally not available to estimate this conditional distribution, practitioners tend to measure 

basis risk as to the linear correlation (or covariance) between the index and a policyholder's 

losses. However, the simple historical correlation between the index and losses may fail to 

accurately assess basis risk because the dependence may not be linear (Collier, Barnett, and 

Skees 2011). Practically, basis risk implies that a policyholder can receive an indemnity that 

is either greater than or less than the actual realized loss. It is even possible that the 

policyholder will suffer a loss and not receive any indemnity. Likewise, the policyholder may 

receive an indemnity without incurring any loss. 

Perhaps the earliest scholarly discussion of agricultural index insurance was Halcrow’s 1949 

article on area yield insurance published in the Journal of Farm Economics. Though Sweden 

introduced an area yield insurance program in 1961 and Quebec did the same in 1977, 

Halcrow’s insight received little attention in the United States until it was revived in a 1991 

article by Mario Miranda in the American Journal of Agricultural Economics. Using a 

Capital Asset Pricing Model (CAPM) conceptual framework, Miranda described how an area 

yield insurance program could provide risk protection for agricultural producers. Then, using 

yield data from west Kentucky soybean producers, Miranda provided empirical evidence of 

the efficacy of an area yield insurance product.

The RMA first facilitated an index insurance offer in 1993. The product was an area yield 

insurance product (then known as the Group Risk Plan, GRP) for soybeans in selected states. 

In 1994, Congress mandated that GRP be expanded “to the extent practicable.” The product 

design and premium rating for GRP were described in Skees, Black, and Barnett (1997). An 

area revenue insurance product (then known as Group Risk Income Protection, GRIP) was 

first offered in 1999. 

Various studies have examined the empirical effectiveness of area yield or revenue insurance 

products. Some of the seminal studies were Hourigan, 1992; Smith, Chouinard, and Baquet, 

1994; Wang et al., 1998; Black, Barnett, and Hu, 1999; Barnett et al., 2005; and Deng, 

Barnett, and Vedenov, 2007. The findings from these studies have generally been that area 

yield insurance products can provide effective risk protection for many, but not all, crop 

producers. However, it is difficult for an area yield insurance product to compete with a 

highly-subsidized insurance product that makes payments based on farm-level losses. 

Over time, interest in agricultural applications of index insurance spread beyond products 

based on indexes that measure aggregate losses over a group to include products based on 

weather indexes that are believed to be highly correlated with losses. In 1988, George Patrick 

published an article in the Australian Journal of Agricultural Economics proposing rainfall 

insurance for wheat farmers in Australia. Skees and Zeuli (1999) proposed rainfall insurance 

products for Australian irrigation water management districts. Others proposed rainfall 

insurance to protect against agricultural losses in India (Hazell, 1992; Gautam, Hazell, and 

Alderman, 1994), Burkina Faso (Sakurai and Reardon, 1997), and Nicaragua (Miranda and 
40

Vedenov, 2001). Weather index insurance products were made available to crop producers in 

India in 2003. 

In its most basic form, weather index insurance makes indemnity payments based on 

realizations of a specific weather variable (e.g., rainfall or temperature) over a defined 

period. The weather variable may be measured at a specific weather station or by other 

means (e.g., satellite). The policy will typically specify a threshold and a limit that establish 

the range of index values over which indemnity payments will be made. For an insurance 

policy that protects against unusually high realizations of the weather variable (e.g., excess 

rainfall or extremely hot temperatures), an indemnity is paid whenever the realized value of 

the index exceeds the threshold. The limit defines the level of the index beyond which no 

additional indemnity payments will be made. If the policy is protecting against unusually low 

realizations of the weather variable (e.g., drought or extremely cold temperatures) an 

indemnity is made whenever the realized value of the index is less than the threshold with the 

limit set lower than the threshold (Barnett and Mahul, 2007). 

Two seminal articles regarding agricultural applications of weather index insurance were 

Martin, Barnett, and Coble’s 2001 article titled “Developing and Pricing Precipitation 

Insurance” in the Journal of Agricultural and Resource Economics and Turvey’s 2001 article 

titled “Weather Derivatives for Specific Event Risks in Agriculture” in the Review of 

Agricultural Economics. After describing the design and pricing of a rainfall index insurance 

product, Martin, Barnett, and Coble demonstrated how such a product could be used to 

protect against the risk of excessive rainfall before and during cotton harvest in the midSouth region of the United States. Turvey, likewise described the design and pricing of 

weather index insurance products for extreme rainfall or extreme temperature events. Turvey 

then demonstrated the efficacy of weather index insurance to protect against corn, soybean, 

and hay yield losses in Ontario. 

Other early articles on weather index insurance include Mahul’s 2001 article on factors that 

impact the optimal choice for various contract parameters, van Asseldonk’s 2003 article 

evaluating agricultural applications of temperature-based weather index insurance in the 

Netherlands, and Vedenov and Barnett’s 2004 article analyzing the efficiency of weather 

index insurance to insure corn, cotton, and soybeans in six U.S. crop reporting districts. A 

common in empirical studies was that the risk-reducing performance of weather index 

insurance varied widely across crops and regions. In one of the first studies to extend beyond 

crop production, Deng et al. (2007) analyzed the potential for insurance based on a 

temperature-humidity index to protect against dairy production shortfalls in the southern U.S. 

Much of the literature on weather-based index insurance has focused on lower-income 

countries. Economists have long recognized that high transaction costs relative to the amount 

of insurance liability make traditional loss-based agricultural insurance products unworkable 

in most lower-income countries. Area yield index insurance is also often not possible due to 
41

limited availability or reliability of official yield data aggregated to a regional level. Since 

weather data are available for many lower-income countries from either ground-based 

weather stations or satellite platforms, weather index insurance is often viewed as a 

potentially viable insurance alternative. 

The literature on agricultural applications of weather index insurance in lower-income 

countries is far too extensive to review here. The following are among the earliest studies in 

this area: Skees 1999; Skees, Hazell, and Miranda 1999; Skees 2000; Skees et al. 2001; 

Hess, Richter, and Stoppa 2002; Varangis, Skees, and Barnett 2002; Skees and EnkhAmgalan 2002; Skees, et al. 2005; Hess et al. 2005; Lilleor et al. 2005; Skees, Hartell, and 

Hao 2006; Hazell and Skees 2006; Kazianga and Udry 2006; Gine ́, Townsend, and Vickery 

2007; J. Skees, Hartell, and Murphy 2007; Chantarat et al. 2007; and, Shynkarenko 2007. A 

common finding in these and subsequent studies is that for some crops in some regions, a 

carefully constructed weather index insurance product can provide significant risk reduction. 

Nevertheless, absent large subsidies, uptake of weather index insurance at the farm level has 

been quite limited. Collier, Barnett, and Skees (2011) is a good resource for information on 

the data required to develop and price weather index insurance while Murphy et al. (2011) 

describe the challenges associated with scaling up weather index insurance offers in lowerincome countries. 

Rating PRF insurance

The current RMA premium rating methodology for the PRF product is described in the 

following documents: (a) the original developer rating methodology document (RMA, 2005), 

and (b) the PRF review conducted by Agralytica (Agralytica, 2014). A PRF premium rate is 

calculated for each grid, interval, and coverage level available to be insured (e.g., over 

400,000 unique rates for the rainfall index-based PRF annually). Rainfall index data are

available from 1948 onwards and serves as the basis for the premium rate calculation. 

The premium rate for each insurable unit is essentially based on a burn rate (BR) approach, 

which is simply the average loss over all historical values of the rainfall index (i.e., where the 

“loss” is just defined as the difference between the actual rainfall index amount and the 

“trigger” index level if index < trigger, zero otherwise). Though the BR method serves as the 

foundation for PRF ratemaking, several parametric distribution-based approaches are also 

utilized (e.g, truncated normal (TN), Black-Scholes (BS), and Gram-Charlier (GC) 

approaches) to supplement rates derived from the BR method. Specifically, rates from these 

distribution-based methods are used to generate upper and lower bounds on the BR-based 

raw rates (e.g., if BR is less than the minimum value from TN, BS, or GC, the smallest 

minimum value among the three distribution-based methods will be used; the same logic 

applies for the maximum). Additional smoothing and catastrophic loading procedures are 

then implemented to calculate the final rates.
42

The literature related to the rating of rainfall-index-based pasture insurance products has been 

limited. However, note that Agralytica (2014) carefully reviewed the rating methodology for 

the PRF product offered by RMA and found that the rating methods used for the rainfallindex-based coverage in PRF were generally appropriate (Agralytica, 2014 p. 102), though 

the report provided some minor suggestions that can potentially improve rating performance 

(e.g., eliminate smoothing and use Limited Expected Value Function rather the BS formulas). 

The Agralytica report also expressed concerns about the high frequency of indemnity 

payments for the PRF program. 

Outside of the aforementioned Agralytica (2014) report, we only found one paper that 

specifically touches on rating issues for rainfall index (RI) based pasture insurance coverage 

– Nadolnyak and Vedenov (2013). Nadolnyak and Vedenov (2013) specifically examine the 

implications of utilizing information on El Nino-Southern Oscillation (ENSO) forecasts in 

the PRF premium rating process. They find that not using ENSO forecast information in the 

rating process can result in intertemporal adverse selection when this ENSO information is 

used by insureds in their participation decisions (i.e., purchasing more coverage when 

expected payouts are high (based on ENSO information), purchasing less coverage when 

expected payouts are low). Therefore, Nadolnyak and Vedenov (2013) recommend 

calculating an ENSO “forecast-conditioned” premium for the PRF insurance product, 

especially for areas nearer the coast (i.e., particularly the Gulf Coast, given that the study 

focused on the Southeastern US as the empirical application).

Most of the published studies that consider rating methodologies for a rainfall-index-based 

insurance product do not specifically focus on the pasture and rangeland case and cover a 

wide variety of crops and contexts. As already mentioned in previous sub-sections of this 

review, an example is the work of Martin et al. (2001), which describes the design and 

pricing of a rainfall insurance product to protect against the risk of excessive rainfall for US 

cotton. Other general rainfall-index insurance articles that describe a variety of rating 

approaches include (among others): Turvey (2001) for several crops in Canada, Vedenov and 

Barrett (2004) for a variety of US commodity crops, Deng et al. (2007) for US dairy, Chen et 

al. (2017) for corn in China, Zhou et al. (2018) for US corn, and Muna et al. (2019) for rice 

in Indonesia. Rating methodologies developed or utilized in these studies range from using 

copulas, parametric distribution models (e.g., Gamma), nonparametric methods (e.g., burn 

rate), mixture models, and combinations of various approaches (where the approach largely 

depends on data availability). 

 Demand for PRF insurance

The demand for crop insurance has a lengthy history. In the modern era, this research was 
43

often predicated on understanding why farmers were not purchasing subsidized individual 

coverage yield insurance. Goodwin (1993), Smith and Baquet (1996), and Coble et al. 

(1996) are early examples of this work. Most of this work found an inelastic demand for 

insurance and some evidence of producers and RMA having differing perceptions of risk. As 

crop revenue insurance became more popular after 1996, researchers turned to understand the 

demand for this new form of crop insurance. Shaik et al. is an example of this literature.

Many of the development papers confirm the basis risk problem (Barnett and Mahul (2007). 

Jensen, Barrett, and Mude (2016) examine the limited acceptance of livestock index 

insurance in a development context. In particular, they focus on direct measurements of basis 

risk. They used longitudinal household data to determine which factors affected the demand 

for index-based livestock insurance. They find that while both price and the non-price factors 

studied previously are important, basis risk and spatiotemporal adverse selection also play a 

major role in determining demand. Kost et al (2012) note that in variable topography regions, 

basis risk is likely more problematic. Elabed, and Carter (2015) note the basis risk problem 

of index insurance and investigate compound-risk aversion, and ambiguity on the willingness 

to pay for index insurance. They note that an index insurance contract appears to the farmer 

as a compound lottery, with uncertainty about individual production outcomes, as well as 

about the validity of the index as a reflection of individual losses. They show that this 

compound lottery structure reduces the demand for index insurance. Field experiments with 

cotton farmers in Southern Mali found that almost 60 percent of farmers are compound-risk 

averse and that the distribution of compound-risk aversion is such that it would nearly cut in 

half the potential demand for the standard index insurance contracts. 

Norton et al. (2014) investigated the demand for differing coverage levels of index insurance. 

They used experimental games with smallholder farmers in Ethiopia. Participants in the 

games allocated money across risk management options including index insurance. 

Participants preferred insurance contracts with higher frequency payouts and insurance over 

other risk management options, including high-interest savings. The authors argue the 

preference for higher frequency payouts affects commercial sales. Wang et al. (2020) 

examine coverage levels and other attributes. They use a labeled choice experiment method 

to investigate Chinese smallholder corn growers’ preferences for alternative insurance 

designs. In addition to traditional yield insurance, they examine farmers’ willingness to pay 

for coverage levels in price, revenue, and weather index insurance, which are currently at the 

experimental stage in China. They found farmer preferences for these various types of 

insurance to be heterogeneous. On average, farmers are willing to pay for all types of 

insurance and for additional coverage but only at the current high subsidy level. They explore 

heterogeneity in willingness to pay and find that farmers’ positive past insurance experience 

plays an important role in their demand for insurance. 
44

Liu et al. (2019) estimate farmers’ willingness to pay (WTP) for a hypothetical excess 

rainfall index insurance contract. In particular, they examine whether recent experience with 

catastrophic flooding influences farmers’ attitudes towards the insurance product. They find 

that farmers from flooded areas have a higher WTP for index insurance than farmers from 

non-flooded areas. 

Several studies have noted non-economic factors influencing index insurance demand. Porth, 

et al. (2015) attempt to explain the factors affecting farmers’ willingness to purchase weather 

index insurance for crops in China, in the Province of Hainan. They conduct a survey of 134 

farmers in Hainan, China, regarding their willingness to purchase weather index insurance. 

The results show that trust of the insurance company is among the significant factors that 

affect the willingness of farmers to purchase weather insurance. Patt et al. (2009) have a 

similar conclusion that the trust that people have in the insurance product and the 

organizations involved in selling and managing it strongly affects demand. They argue that 

data from India, Africa, and South America show that these factors may be more important 

than the economic factors in influencing demand. Gaurav, Cole, and Tobacman (2011) 

focused on farmer education and the demand for rainfall insurance in India. They 

specifically researched the implication of financial literacy as a determinate of insurance 

demand. The authors found that financial education has a positive and significant effect on 

rainfall insurance adoption, increasing take-up from 8 percent to 16 percent. Also, a moneyback guarantee has a consistent and large effect on farmers' purchase decisions. 

Ifft, Wu, and Kuethe (2014) examined the impact of publicly supported insurance on 

agricultural land values. Implicitly this analysis relates to the demand for subsidized 

insurance. The analysis employs confidential, nationally representative panel data on fieldlevel pastureland values and exploits a natural experiment provided by gradual introduction 

of the Pasture, Rangeland, and Forage Insurance Pilot Program. They use a field-level fixedeffects model that controls for several time-variant factors and find that insurance availability 

is associated with an increase of at least 4 percent in pastureland values. This increase is 

comparable with increases generated by other government programs but is much smaller than 

the total farmland value increases experienced in recent years.

The study most directly applicable to the U.S. PRF program is likely that of Goodrich, Yo, 

and Vandeveer (2019). These authors specifically examine PRF participation in Kansas and 

Nebraska from 2013 to 2017. They pay particular attention to the intervals chosen by 

purchasers of the PRF product. They note many producers purchase insurance that provides 

coverage outside the forage growing season. Empirically this behavior appears to be 

growing over time. Conceptually, the authors note that because the subsidy rate is equal

across all 2-month intervals and the intervals in the non- growing season have higher 

premiums, allocating more liability to the non-growing season increases the expected profit 
45

(assuming actuarial fairness of the premium). The authors conceptualize purchase in nongrowing periods may be attributed to a less risk-averse preference. However, they suggest 

that premium subsidies and producer returns associated with non-growing season months are 

often greater than those for growing season months. The authors also conclude crop 

insurance agents may be suggesting strategies for participants to maximize the chance of 

receiving an indemnity by placing some of their liability into non-growing season months. 

Advances in index insurance since 2010

As mentioned in the first section of this literature review, there has been tremendous growth 

in the number of studies on agricultural index insurance over the last twenty years. Review 

articles by Miranda and Farrin (2012), Carter et al. (2014), Di Marcantonio and Kayitakire 

(2017), and Jensen and Barrett (2017) have all carefully summarized advances in the extant 

literature on agricultural index insurance, examined experience with agricultural index 

insurance in various countries, and identified lessons learned and challenges for the future. 

But note that these articles primarily focused on experience with agricultural index insurance 

in developing countries (though some of the general issues discussed apply to a developed 

country context as well). In general, these review articles pointed out that agricultural index 

insurance has great potential as a risk transfer mechanism for poor agricultural households in 

developing countries. However, a common observation is that the “track records” of these 

agricultural index insurance offerings have largely been disappointing. Each of these review 

papers then goes on to discuss the potential problems (or issues) that have likely caused these 

disappointing results in developing countries and make suggestions on how these issues can 

be addressed. Recommendations for future actions and research agendas to improve the 

performance of agricultural index insurance in developing countries are discussed. 

Most of the aforementioned review articles divide the issues affecting the disappointing 

performance of agricultural index insurance in developing countries into the demand-side 

and supply-side factors. The demand-side factors frequently mentioned are: premium 

affordability, lack of trust in insurance providers, financial literacy of target households 

(linked to poverty levels), cognitive and behavioral issues (e.g., ambiguity aversion, 

compound risk aversion), and general low willingness to pay (or demand) for these products. 

For this report, the more pertinent lessons from these review papers may be the supply-side 

factors that have influenced the performance of index insurance programs in developing 

countries. The most common supply-side issues mentioned are: basis risk (and related quality 

of index design issues), lack of quality data, institutional and government support issues (i.e., 

lack of enabling environments, delivery mechanisms, regulatory mechanisms, etc.), and 

issues with reinsurance markets (e.g., reinsurance charging high uncertainty premiums, 

driving up index insurance premiums). 
46

As would be expected, all of the review articles cited above overwhelmingly raised the 

supply-side issue of basis risk (as related to the quality of the product design) and discussed 

ideas that may help reduce it. Dalhaus and Finger (2016) categorize basis risk into three 

components: spatial, temporal, and design. Spatial basis risk occurs when the index is not 

measured at the same location as the underlying insured crop is situated. This, for example, 

occurs when indices are based on measurements from remote weather station(s) far from the 

insured crop. Temporal basis risk emerges due to a biased temporal aggregation of 

observations, mainly because observations are aggregated into months (or seasons or years), 

while the risk vulnerability of plants is more related to plant phenological phases (Conradt et 

al., 2015; Dalhaus et al., 2018). Design basis risk is present when the chosen underlying 

index is not a good approximation of the underlying sources of yield or revenue variability. 

Given these basis risk categories, much of the recommendations put forth by the review 

articles mentioned above try to address some aspect of these basis risk types. 

Carter et al. (2014) suggest that solutions that can minimize basis risk can be classified as 

technological, contractual, and institutional. Much of the technological solutions involve the 

collection and use of better quality data that can further reduce spatial, temporal, and design 

risks. Technological suggestions in this vein include the use of indices with finer resolutions 

(e.g., gridding, spatial interpolation, etc.), use of more advanced satellite and remote sensing 

images (as the primary or a complementary index), and use of mobile weather stations (to 

increase coverage). Satellite and remote sensing data are viewed as potential paths to reduce 

spatial basis risk (e.g., better spatial coverage), temporal basis risk (e.g., better coincide index 

to the timing of loss), and design basis risk (e.g., may better correlate with actual losses). But 

note that empirical evidence as to the performance of these satellite or remote sensing-based 

index insurance designs is still lacking. Some contractual solutions suggested by Carter et al. 

(2014) include the use of secondary, backup, or audit indices (or triggers). The use of index 

insurance at higher levels of aggregations (e.g., meso-level index insurance for cooperatives) 

has also been recommended. 

Contractual changes that better match the time window of actual crop losses to the time 

window for the index offering have also been shown to improve temporal basis risk. For 

example, Conradt et al. (2015), Dalhaus and Finger, 2016, and Dalhaus et al., 2018 have 

shown that index insurance contracts that are more closely tied to the phenological growth 

phases of the underlying cash crop being insured are better able to insure losses (more on this 

below as it relates to PRF). Lastly, institutional solutions include efforts to develop 

institutions (governmental or otherwise) to improve quality standards for index insurance 

offerings, better targeting of initial pilot sites, better design of subsidies (e.g., smart 

subsidies), support of informational and educational efforts, bundling index insurance 

offerings with credit (or other financial instruments), and further research on the impacts of 

index insurance (as well as behavior towards risk and insurance). Another common 
47

recommendation is to conduct research that measures basis risk for particular index products 

offered, which involves the collection of farm-level yield/loss data in index coverage areas to 

assess the performance of these products. 

Even though there is a robust literature on agricultural index insurance and there are several 

review articles that have summarized advances and identified limitations/challenges, studies 

that specifically focused on index insurance for pasture, rangeland, and forage (PRF) (or socalled grassland-based agricultural systems) have been limited. Nonetheless, the review 

article by Vroege et al. (2019) provides an important discussion of advances and challenges 

with regards to index insurance for PRF in the US and Europe. First, Vroege et al. (2019) 

find that three different insurance types exist in the US and Europe: area-yield-based (like 

Area Risk Protection Insurance (ARPI) in the US), weather-index-based, and satelliteimagery-based. They find that the single weather-index-based types are the predominant type 

offered for PRF coverage. Second, Vroege et al. (2019) point to the potential of using 

advances in satellite and remote sensing technologies in developing PRF index insurance 

products. The article noted that indices based on satellite or remote sensing measures related 

to yields and the plant growth environment have the potential for innovative index insurance 

designs. 

Recent studies by Bacchini and Miguez (2015) in Argentina, Roumiguie et al. (2017) in 

France, and Jensen et al. (2019) in Kenya also largely point to the potential effectiveness of 

offering satellite-based index insurance contracts. In particular, a recent paper on the PRF 

design in the US by Williams and Travis (2019) find that a PRF index insurance offering

based on a drought index performs better than when a rainfall index is used (as is currently 

done). Williams and Travis (2019, p. 629) further suggest that “drought indices have a higher 

correlation with range production, a tendency to incentivize growing-season protection, more 

even geographic distribution of risk, reduced policyholder ability to seek higher payments 

through strategic coverage choices, and increased provider ability to adjust payment patterns 

to reduce the risk of nonpayment given loss.” 

However, Vroege et al. (2019) still note that past index insurance offerings based on satellite 

images of the normalized difference vegetation index (NDVI) have had limited success. 

Thus, Vroege et al (2019) recommend further study and development of a satellite-based 

index design that: (a) has an area-yield format using alternative satellite measures of 

vegetative growth (e.g., more transparent measures than NDVI such as the Forage Production 

Index (FPI) in France that measures the fraction of the ground covered by grass), (b) has an 

area-yield format that uses imagery to supplement index construction, (c) uses a satelliteimagery-based weather index (rather than a satellite-based measure of the vegetation itself 

like NDVI), and (d) has a double-trigger approach where the trigger is based on satellite 

imagery vegetation and/or weather measures. Even with these recommendations, however, 
48

the authors point out that the use of more complex indices that can reduce basis risk may 

result in reduced transparency and possibly increased moral hazard (e.g., this tradeoff exists 

especially for vegetative indexes of high resolution). 

The Vroege et al. (2019) paper also highlighted better matching of phenological growth 

stages of the underlying crop to the structure of the index insurance window(s) as another 

potential avenue for reducing basis risk (specifically, temporal basis risk) and improving the 

performance of agricultural index insurance. As already alluded to above, Conradt et al. 

(2015), Dalhaus and Finger (2016), and Dalhaus et al. (2018) have shown that index 

insurance contracts that are more closely tied to the phenological growth phases of the 

underlying cash crop being insured can reduce temporal basis risk and perform better (e.g., 

better downside risk protection). 

Since Yu et al. (2019) find that spatial basis risk for PRF in Kansas and Nebraska is likely 

less important relative to temporal and design basis risks, further improvements in PRF 

contract structure in terms of more closely tying the PRF contract design to the most 

vulnerable PRF growth phases may help improve performance. Note that in the current PRF 

design, insureds can choose to insure at least two fixed two-month intervals (as long as they 

are not adjacent) and can assign coverage levels and liability weights on each period insured. 

However, Belasco and Hungerford (2018) find that in the US Mountain West region 

producer selections of time intervals are spread fairly evenly throughout the year, despite

rainfall during late spring and early summer being the most critical to grass growth in this 

region. Many producers choose to insure during the winter months despite little evidence that 

forage production is impacted by snowpack (Frank, 1973). In a study that explores optimal 

interval choice for PRF in South Dakota, Diersen et al. (2015) suggest that the most risk 

efficient intervals are May-June and July-August and these choices are most consistent with 

the desire to have payments that offset the highest expected forage risk. Westerhold et al. 

(2018) also find that intervals that coincide with the actual growing season in Nebraska are 

the ones where PRF provides the largest risk reductions. This study recommended dropping 

intervals in the PRF contract that do not coincide with the growing season since these 

intervals tend to be used as an income maximizing strategy rather than for risk reduction. 

Maples et al. (2016), in a study of the Rainfall Index Annual Forage pilot program (RIAFP), 

which is similar in structure to the PRF offering, find that the rainfall index used has a high 

correlation with actual rainfall, but does not correlate very well with actual forage yields in 

their data (e.g., design basis risk). Maples et al. (2016, p. 47) also suggest that the 

performance of RIAFP may improve by including intervals that closely match the time of 

production. In general, these studies seem to suggest that there may be merit to exploring 

PRF contract design modifications with regards to PRF intervals (e.g., intervals offered, 

interval lengths, interval availability, interval weight limits, and available interval coverage 

level choices) being more closely matched to the region-specific growing season (or 
49

phenological growth states). Modifications here may also help address concerns about the 

frequency of “shallow” PRF payments across different intervals. 

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57

Chapter 4 Review and analyze the methods used in the development of 

the expected rainfall amount

Discussion of Data

The PRF product bases coverage on recorded precipitation made across an extensive 

network of weather stations. The specific source for the accumulated rainfall data used to 

construct the rainfall index is the National Oceanic and Atmospheric Administration’s 

(NOAA) Climate Prediction Center (CPC). These data are available back to 1948 and 

consist of spatially smoothed and interpolated measures of monthly rainfall. These data are 

smoothed to provide a resolution of 0.25 degrees, which is approximately 28 square 

kilometers. The CPC data only report precipitation and do not consider other weather 

variables that may also be relevant to the condition of pasture, rangeland, and forage. 

In a separate department of NOAA, the National Climate Data Center, a similar gridded set 

of data is available. These data also include temperature (monthly high, low, and average) 

and report data back to 1895. The NCDC data are available on a much finer grid, providing 

measures at the 1/24th degree level of resolution (about a 4 square kilometer grid). Thus, the 

resolution of the NCDC data is about 36 times greater than that of the CPC. Discussions 

with the NOAA scientist in charge of providing the NCDC data, Russell Vose, indicated 

that the two alternative sources of weather data are largely independent and are constructed 

by different teams using different smoothing algorithms. Concerns have been raised as to 

the timeliness of the NCDC data (i.e., the time lag associated with providing near real-time 

weather observations) and the extent to which the climate data may be subject to 

retrospective revisions. We do not believe that such concerns necessarily present any 

legitimate barriers to basing coverage on the NCDC data.5

Finally, other suitable weather data sets are publicly available and could be used to develop 

rates and terms of coverage for PRF. NOAA produces a couple of data sets that are in 

addition to those noted above. Primarily, the PRISM data are synthesized from NOAA’s 

station-level data and are available from Oregon State University. These data are essentially 

analogous to the NCDC data. The data are also provided on a 4 square kilometer grid and 

include precipitation, minimum temperature, maximum temperature, and average 

temperature. Station-level data, such as NOAA’s NCEI (National Centers for 

Environmental Information) data, also offer detailed data on a worldwide range of climate 

5 In an email exchange, Dr. Vose reported that the NCDC data are released on the first day into the month 

subsequent to the observations to coincide with the monthly Climate Report. He also indicated that the data are 

typically not subject to revisions once released. 
58

variables. Station data could certainly be interpolated as is the case for the existing CPC 

and NCDC data and therefore used to form a grid. However, we see no utility in repeating 

the spatial smoothing used by NOAA to grid the NCDC and CPC data for the station-level 

data. 

In a fashion similar to that considered for the NCDC data, we aggregated the PRISM 

precipitation data and undertook a comparison to the CPC data currently in use. A 

comparison of the CPC and aggregated PRISM data are presented below. The comparison 

indicates that, again, similar differences in the alternative measures of precipitation are 

apparent. The degree of difference appears to be slightly higher in the case of the PRISM 

data, though both diagrams indicate substantial differences, even in very dry or very wet 

conditions. Finally, we directly compared similarly aggregated CPC and PRISM data. 

The differences in precipitation measurements obtained from the alternative sources have 

been noted in the literature. Gao et al. (2017) compared the NCDC, PRISM, and data 

consolidated from the NEXRAD weather monitoring system.6

 Figure 4-7 reproduces a 

diagram from their paper that demonstrates the differences observed in a comparison of 

NEXRAD and PRISM data. 

We see no reason to necessarily prefer one data source over another. Absent any “groundtruthing” that would be made by comparing to actual precipitation, there is no tangible way 

to compare one data set to another. The advantages of PRISM and NCDC data include a 

finer (4km) grid and a much longer history. Further, these two data sets contain additional 

climate variables, including temperature extremes. If, at some point in the future, an index 

that considers both temperature and precipitation could be constructed, the alternative 

NCDC data might offer advantages. This would require the construction of an index that 

accurately specifies the relationship between forage output, heat, and precipitation. We 

considered state-level yield and price data to evaluate the relationship between heat, 

precipitation, and hay yields. Likely because of the very aggregate nature of the NASS 

yield data (at the state level), we were unable to adequately define an index that relates both 

temperature and precipitation to hay yields, even though the relevant literature has 

determined that both variables are relevant to hay yields. 

 

One alternative to incorporating temperature into the PRF coverage would be to establish 

dual thresholds that provide a dual trigger that would result in indemnity payments. If a 

threshold of extreme temperature beyond which hay is damaged could be defined, it may be 

possible to include a temperature trigger that would also result in indemnities. For example, 

6 Gao, J., A. Y. Sheshukov, H. Yen, and M. J. White. “Impacts of alternative climate information on hydrologic 

processes with SWAT: A comparison of NCDC, PRISM and NEXRAD datasets,” Catena, 156, September 2017, 353-

364.
59

if it could be established that hay yields fall, regardless of available moisture, at temperature 

maximums of 95 degrees or higher, an indemnity could be paid solely based on the high 

temperature. Rating such coverage would be trivial in that it could be handled exactly as the 

rainfall index is currently applied. However, much as is the case with the County Base 

Values (CBV), the payoff schedule is problematic. 

An additional finding that merits discussion relates to any differences that may exist 

between the NCDC and CPC sources of precipitation. We aggregated the finer NCDC 

precipitation data to a similar level of aggregation underlying the CPC data and compared 

the two alternative measures of monthly rainfall. Figure 4-1 illustrates relationships 

between the two alternatives across a wide geography that includes a large portion of the 

Corn Belt and Great Plains.7 The figure demonstrates the fact that alternative rainfall 

measures can be very different. This naturally reflects the differences in smoothing and 

reporting algorithms. 

We believe that this does raise an important policy consideration for RMA. The differences 

highlight the fact that alternative measures of rainfall at specific points in the network of 

Grid Codes currently used by the RMA (from the CPC data) can be very different. This 

challenges the fundamental framework of basing coverage on a finely defined grid. If 

pasture and rangeland are sensitive to precipitation shortfalls, one would need an accurate 

measure of precipitation for establishing the terms of coverage. The comparison of the 

alternative NOAA sources on monthly rainfall indicates that the relationship between 

measured rainfall and hay and pasture yields is inaccurate. This is because significant 

differences between two equally valid measures of rainfall are apparent and the accuracy of 

either measure is unknown. This is a natural result of using synthesized data where the data 

are generated using different methods. 

One would expect that these differences would be much smaller for more aggregated data. 

Figures 4-2 and 4-3 present the two alternative measures of monthly rainfall aggregated to 

the county and state levels, respectively. The differences do indeed diminish when a higher 

level of aggregation is considered, though meaningful differences persist across aggregation. 

Of course, alternative sources of the county and state level rainfall measurements are 

available.8

 We recommend that RMA consider basing coverage on rainfall measured at a 

higher level of aggregation—possibly the county or NOAA weather district. Using districtlevel data has another important advantage in that an array of different weather variables, 

including numerous soil moisture and drought indicators, are available. Such variables may 

7 We included the area spanned by longitudes between -102 and -98 degrees and latitudes between 40 and 44 

degrees. Figure 2-4 below illustrates this area, which also formed the basis for our extensive evaluation of 

premium rates. We aggregated all NCDC grid points that were within 15 kilometers of the centroid of the CPC grid 

points.

8 The NCDC reports county level data on rainfall and precipitation. 
60

exhibit a stronger relationship with pasture, rangeland, and hay yields. 

Trend Analysis

The extent to which measurable changes in precipitation patterns may exist is also an 

important consideration. Such changes may appear as statistically significant trends or 

changes in patterns of seasonality, or both. We randomly selected 100 grid IDs and fit the 

trend and seasonal cycles to each of the points using the CPC data from 1948-2017. We 

used a first-order Fourier series expansion to capture cyclical seasonality patterns across 

different months of the year. Examples of the predicted trend and cyclical patterns are 

presented below in Figures 4-7 through 4-9. It is important to note that any deliberate 

adjustments to compensate for any implied trend or structural breaks reflecting climate 

change would necessarily lower premium rates. Such an adjustment removes variability 

from the precipitation data and thus decreases the amount of unexplained variability in 

historical precipitation patterns. In light of the considerable debate surrounding the climate 

change issue and the effect of lowering premium rates, we do not recommend explicit 

changes that would remove trends or that would account for structural change unless such 

changes are large and unambiguously apparent. The existing scientific evidence as well as 

the following statistical tests of trends and structural change do not, at present, provide such 

unambiguous conclusions regarding climate change and we thus do not recommend any 

changes to the sample sizes or incorporation of trends or structural change. 

Table 4-1 presents only the trend parameter estimates for the 100 randomly selected IDs. 

The results indicate a statistically significant trend effect in most cases, although the trends 

that are implied are almost always very small. The statistical significance of the trend 

parameters reflects the significantly large number of monthly observations available for 

analysis. We do not recommend any changes in current rating procedures that would 

incorporate these small trend effects. 

We also divided the precipitation data into two halves and considered standard Chow tests 

of structural changes in the seasonal and trend components. The results of these tests are 

presented in Table 4-2. The Chow test results suggest structural breaks in a minority of 

cases. In light of the impact of lowering rates and that there is greater ambiguity regarding 

the effect of climate change on rainfall intervals than for temperature and storm intensity, 

we do not recommend incorporating structural breaks into the rating process. 

Data Recommendations

RMA should continue to use the NOAA CPC precipitation data. Alternative data sets 
61

(PRISM, NCEI, NEXRAD, NCDC) offer no real advantages and, in the case of the NCEI, a 

disadvantage in that the data are not “gridded” but rather are reported at the station level. 

The absence of any “ground-truthing” obviates any tangible approach to selecting one data 

set over another on the grounds of accuracy. Each of the alternatives exhibits significant 

differences concerning the CPC data currently used (and with one another). These 

differences must be acknowledged but we recommend no changes to the current data used to 

rate and design coverage.

Although trends and structural breaks are sometimes identified in the precipitation data, 

such changes over time are always small and are not consistent across different grid IDs. 

Any attempt to explicitly account for trends or structural breaks will have the effect of 

lowering premium rates. In the absence of firm scientific conclusions regarding climate 

change effects on rainfall periods, we recommend that RMA continue to use the full 1948-

present CPC data in its entirety and without explicit adjustments meant to reflect climate 

change.
62

Table 4-1 Trend Parameter Estimates in Precipitation Data

NOAA Value Statistically

GRID Trend Standard t Probability Significant

ID Estimate Error Statistic t-Stat p<.05

18129 1.9968 0.8982 2.22 0.0265 *

18415 0.3771 0.5662 0.67 0.5055

18695 0.3107 0.3513 0.88 0.3768

18714 -0.5346 0.5388 -0.99 0.3214

18990 1.1471 0.2896 3.96 0.0000 *

19013 0.1648 0.5456 0.3 0.7626

19014 0.2533 0.5276 0.48 0.6312

19021 1.4258 0.6639 2.15 0.0320 *

19033 2.2183 0.8821 2.51 0.0121 *

19284 1.0125 0.3546 2.86 0.0044 *

19317 0.5197 0.5824 0.89 0.3724

19335 2.5977 0.9114 2.85 0.0045 *

19336 1.7356 0.908 1.91 0.0563

19922 0.2414 0.6638 0.36 0.7162

19926 1.7016 0.76 2.24 0.0254 *

19939 3.2134 0.9805 3.28 0.0011 *

20218 0.9314 0.5901 1.58 0.1148

20234 2.0079 0.9093 2.21 0.0275 *

20786 0.043 0.3988 0.11 0.9142

20803 1.0154 0.3682 2.76 0.0059 *

21109 1.4307 0.4376 3.27 0.0011 *

21119 1.7537 0.6249 2.81 0.0051 *

22029 2.2398 0.7446 3.01 0.0027 *

22035 0.7275 0.8518 0.85 0.3933

22324 1.0332 0.637 1.62 0.1052

22575 1.04 0.364 2.86 0.0044 *

22584 1.0392 0.3121 3.33 0.0009 *

22587 1.7566 0.2899 6.06 0.0000 *

22594 1.8038 0.3977 4.54 0.0000 *

22625 0.1396 0.6641 0.21 0.8336

22635 2.0973 0.8609 2.44 0.0150 *

22915 1.5607 0.4915 3.18 0.0015 *

22934 1.6176 0.821 1.97 0.0491 *

22935 1.3317 0.8253 1.61 0.1070

23201 1.1539 0.3896 2.96 0.0031 *

23474 2.0420 0.3994 5.11 0.0000 *

24103 -0.058 0.3609 -0.16 0.8723

24113 0.4957 0.455 1.09 0.2763

24414 1.4844 0.4936 3.01 0.0027 *
63

NOAA Value Statistically

GRID Trend Standard t Probability Significant

ID Estimate Error Statistic t-Stat p<.05

24687 0.0353 0.3011 0.12 0.9068

24711 0.467 0.4455 1.05 0.2949

25037 1.1449 0.7695 1.49 0.1371

25270 1.9066 0.3269 5.83 0.0000 *

25301 1.1044 0.3613 3.06 0.0023 *

25593 5.4909 0.3688 14.89 0.0000 *

25874 0.9399 0.5409 1.74 0.0826

25879 1.9843 0.2524 7.86 0.0000 *

26177 1.5708 0.3447 4.56 0.0000 *

26178 1.6778 0.3382 4.96 0.0000 *

26224 2.9097 0.5784 5.03 0.0000 *

26816 0.9557 0.4876 1.96 0.0503

26817 0.5159 0.4801 1.07 0.2829

27125 1.2333 0.5453 2.26 0.0240 *

27394 2.1212 0.3804 5.58 0.0000 *

27436 0.8047 0.625 1.29 0.1983

27974 2.7835 0.4128 6.74 0.0000 *

27996 0.8098 0.4008 2.02 0.0437 *

28280 4.8567 0.4718 10.29 0.0000 *

28307 1.689 0.4421 3.82 0.0001 *

28314 0.2698 0.4390 0.61 0.5391

28566 0.5178 0.4398 1.18 0.2394

28576 1.892 0.4473 4.23 0.0000 *

28580 5.6791 0.5733 9.91 0.0000 *

28591 3.4719 0.3426 10.13 0.0000 *

28888 0.7547 0.2415 3.12 0.0018 *

29176 -0.7248 0.8002 -0.91 0.3653

29193 0.9221 0.4603 2 0.0455 *

29218 1.5464 0.4564 3.39 0.0007 *

29465 0.713 0.3514 2.03 0.0428 *

29467 5.1334 0.3331 15.41 0.0000 *

29472 1.1218 0.4454 2.52 0.0120 *

29813 1.0682 0.4462 2.39 0.0169 *

29816 1.3033 0.4824 2.7 0.0070 *

30066 1.5755 0.5797 2.72 0.0067 *

30667 0.1329 0.336 0.4 0.6926

30674 2.8203 0.3967 7.11 0.0000 *

30708 0.8404 0.41 2.05 0.0407 *

30723 1.8726 0.4875 3.84 0.0001 *

30965 -0.4044 0.4456 -0.91 0.3644
64

NOAA Value Statistically

GRID Trend Standard t Probability Significant

ID Estimate Error Statistic t-Stat p<.05

30983 0.8276 0.3975 2.08 0.0376 *

30995 0.9872 0.4239 2.33 0.0201 *

30996 1.0447 0.4264 2.45 0.0145 *

30999 1.3399 0.4289 3.12 0.0018 *

31003 1.4633 0.4189 3.49 0.0005 *

31005 1.4032 0.411 3.41 0.0007 *

31013 0.3181 0.4161 0.76 0.4448

31270 0.4681 0.3511 1.33 0.1828

31309 -0.0761 0.4501 -0.17 0.8658

31565 0.6407 0.4653 1.38 0.1689

31566 4.5922 0.4251 10.8 0.0000 *

31572 3.72 0.372 10 0.0000 *

31588 1.4953 0.3830 3.90 0.0001 *

31595 1.0195 0.4037 2.53 0.0117 *

31624 1.5624 0.4773 3.27 0.0011 *

31625 1.634 0.5092 3.21 0.0014 *

31640 -1.0246 0.6027 -1.70 0.0895

31886 1.4889 0.3878 3.84 0.0001 *

31917 1.2838 0.4754 2.7 0.0071 *

31933 1.98 0.5133 3.86 0.0001 *

32220 1.5336 0.4903 3.13 0.0018 *
65

Table 4-2. Chow Tests of Structural Breaks in Precipitation Trends and Cycles 

NOAA Value Statistically NOAA Value Statistically

GRID t Probability Significant GRID t Probability Significant

ID Statistic F-Stat p<.05 ID Statistic F-Stat p<.05

18129 0.96 0.4260 26816 0.69 0.5978

18415 0.72 0.5751 26817 0.69 0.6016

18695 1.78 0.1306 27125 0.54 0.7064

18714 2.39 0.0493 * 27394 5.15 0.0004 *

18990 1.77 0.1327 27436 0.32 0.8624

19013 1.33 0.2587 27974 3.93 0.0036 *

19014 1.31 0.2639 27996 1.71 0.1465

19021 0.92 0.4514 28280 9.30 0.0000 *

19033 1.05 0.3781 28307 0.45 0.7707

19284 0.28 0.8938 28314 0.44 0.7769

19317 0.71 0.5827 28566 5.77 0.0001 *

19335 1.31 0.2652 28576 3.51 0.0075 *

19336 0.87 0.4794 28580 11.51 0.0000 *

19922 1.17 0.3209 28591 1.84 0.1188

19926 0.37 0.8314 28888 0.33 0.8545

19939 0.69 0.5991 29176 17.55 0.0000 *

20218 0.45 0.7709 29193 0.90 0.4662

20234 1.40 0.2310 29218 1.46 0.2136

20786 3.69 0.0055 * 29465 9.33 0.0000 *

20803 5.15 0.0004 * 29467 18.20 0.0000 *

21109 6.04 0.0000 * 29472 0.34 0.8509

21119 0.24 0.9170 29813 0.26 0.9021

22029 0.58 0.6794 29816 1.16 0.3290

22035 0.48 0.7483 30066 17.60 0.0000 *

22324 0.12 0.9761 30667 3.25 0.0118 *

22575 4.27 0.0020 * 30674 8.07 0.0000 *

22584 0.95 0.4370 30708 1.46 0.2139

22587 1.19 0.3156 30723 2.62 0.0338 *

22594 2.09 0.0799 30965 1.03 0.3885

22625 0.10 0.9814 30983 0.74 0.5671

22635 0.71 0.5872 30995 1.61 0.1701

22915 0.49 0.7440 30996 1.54 0.1878

22934 0.22 0.9273 30999 1.35 0.2491

22935 0.24 0.9140 31003 1.11 0.3483

23201 2.64 0.0327 * 31005 0.53 0.7124

23474 8.56 0.0000 * 31013 0.54 0.7040

24103 0.81 0.5215 31270 4.02 0.0031 *

24113 0.80 0.5263 31309 1.56 0.1823
66

NOAA Value Statistically NOAA Value Statistically

GRID t Probability Significant GRID t Probability Significant

ID Statistic F-Stat p<.05 ID Statistic F-Stat p<.05

24414 0.53 0.7131 31565 18.67 0.0000 *

24687 7.78 0.0000 * 31566 8.30 0.0000 *

24711 0.64 0.6353 31572 7.29 0.0000 *

25037 0.91 0.4547 31588 1.19 0.3149

25270 2.76 0.0266 * 31595 0.62 0.6489

25301 1.14 0.3341 31624 1.64 0.1615

25593 13.44 0.0000 * 31625 1.61 0.1697

25874 6.47 0.0000 * 31640 2.82 0.0242 *

25879 2.10 0.0786 31886 0.75 0.5574

26177 4.23 0.0021 * 31917 0.85 0.4949

26178 1.93 0.1026 31933 0.71 0.5870

26224 1.48 0.2058 32220 2.04 0.0865

Figure 4-1
67

Comparison of NCDC and CPC NOAA Data

Figure 4-2

Comparison of PRISM and CPC NOAA Data
68

Figure 4-3

Comparison of PRISM and NCDC NOAA Data
69

Figure 4-4

Comparison of NEXRAD and PRISM Precipitation Measures from Gao 

et al. (2017) 
70

Figure 4-5 

Comparison of NCDC and CPC NOAA Data at County Level 
71

Figure 4-6

Comparison of NCDC and CPC NOAA Data at State Level
72

Figure 4-7

Estimated Trend and Seasonality for ID 19014 
73

Figure 4-8

Estimated Trend and Seasonality for ID 19033 
74

Figure 4-9

Estimated Trend and Seasonality for ID 19335 
75

Rating Review

The current procedure used in rating the PRF product utilizes a nonparametric empirical burn 

rate and parametric distributions derived from the log-normal and the truncated normal. 

Because there are currently only 70 years of rainfall data available (in the CPC data currently 

used by RMA), the use of an empirical burn rate might be questionable. One would typically 

hope to have a longer range of data if departing from any specific parametric distribution in 

rating coverage. The fact that RMA’s process includes a comparison of the burn rates to 

rates taken from the lognormal, truncated normal, and a Gram Charlier (GC) expansion 

distribution in order to bound the final rate serves to mitigate this concern. One would 

expect that parametric distributions would tend to smooth rates and result in slightly higher 

rates in high-risk cases. An alternative approach could consider smoothing rates and adding 

a modest amount of structure by applying nonparametric kernel density estimation methods. 

 

The specific bounding undertaken by RMA is the rating process involves the following steps. 

1. Calculate the burn rate and rates implied by the BS/lognormal, GC, and truncated 

normal.9

2. If the burn rate is less than the maximum of the truncated normal, the BS/log-normal, 

and the GC rates, the raw rate is set to the lowest of the three different parametric rates.

3. If the burn rate is higher than the maximum of the three parametric rates, the raw rate is

set to the maximum of the parametric rates. 

4. If the burn rate is between the minimum and maximum of the parametric rates, the raw 

rate is set to the burn rate. 

5. The raw rate is then loaded by dividing by 0.88. 

After a final raw rate is derived, a spatial smoothing algorithm that takes a weighted average 

of the raw rate and surrounding raw rates is used to determine a final rate. It should be noted 

that this weighting scheme is reasonable though it is of an ad hoc nature. One could combine 

the neighboring grids before estimating a final raw rate, though there is no reason to prefer 

such over the present method. The spatial smoothing practice is entirely reasonable and we 

do not recommend any changes to current smoothing practices. However, it may be relevant 

to consider how rates might differ if the pooling was done before the specific rates were 

calculated. 

The bounding of rates through a comparison of the burn rate with the three parametric 

alternatives is a sensible approach. However, it is ad hoc and lacks any real justification. An 

alternative that may have merit would be to use specific criteria that reflect the goodness of 

9 The developers use a Black Scholes (BS) option pricing model formula to calculate a distribution analogous to a 

lognormal. As we note below, we believe an error exists in the coding of the BS estimates. The developers also 

use a Gramm Chatalier. 
76

fit of the parametric alternatives as a means of selecting a final parametric rate. We discuss 

the application of such an approach next. 

We broadened the consideration of parametric distributions to include the Weibull, Normal, 

Inverse Gaussian (Wald), and the Gamma distributions. We calculated various measures of 

standard goodness of fit tests of each of these distributions. Specifically, we considered the 

Anderson-Darling, Cramer von Mises, and Kolmogorov distributional tests. Not every test is 

available for every distribution considered, though each candidate is tested using at least two 

goodness of fit tests. 

We considered the following alternative distributions: 

PPPPPP(′WWWWWWWWWWWW ′, xx, aa, λλ) = {

0 xx < 0

ee ee(−(

xx

λλ

)aa)

aa

λλ (

xx

λλ

)aa−1 xx ≥ 0

PPPPPP(′

GGGGGGGG ′, xx, aa, λλ) = {

0 xx < 0

1

λλaaΓΓ(aa)

xxaa−1ee ee(− xx

λλ

) xx ≥ 0

PPPPPP(′ IIII IIII GGGG GG ) = [

λλ

2ππxx3]

1 2⁄ exp {− λλ

2μμ2xx (xx − μμ)2},         xx > 0

PPPPPP(′ LL ′, xx, θθ, λλ) = {

0 xx ≤ 0

1

xxxx √2ππ

ee ee(− (llllll(xx)−θθ)2

2 2 ) xx > 0. 

A selection of 8 randomly chosen grids and intervals is presented in Figures 4-10 to 4-12. 

The range of densities illustrates that the density is quite similar, except for the normal 

density. The densities that admit a greater degree of negative skewness will tend to generate 

higher rates. This is illustrated by the shape of the distribution, with the mode falling closer 

to zero than is the case for other distributions. The highest rates would be expected to be 

observed for the inverse Gaussian distribution---a result that is confirmed below. The top 

diagram in Figure 4-12 illustrates the problems associated with fitting the parameter 

distribution to counties that typically have very dry climates. 

The tests were calculated for every grid code and interval combination (149,866 cases). The 

tests provide strong support for the truncated normal distribution, which is rejected at the 5 

percent level only in 3-10 percent of the cases. However, a similar degree of fit is offered by 

the Gamma distribution, which is rejected in only about 8-10 percent of the cases. Rather 

than using an ad hoc procedure to select the distribution for parametric rates, we recommend 

that RMA consider using an alternative approach that can be justified on statistical grounds. 

The goodness of fit tests could be compared to one another to select the best fitting 

distribution. Table 4-3 presents a summary of the test results for all grids and intervals. 

Table 4-4 reports results by interval and distribution. 
77

Table 4-3 

Goodness of Fit Tests Calculated from All Grid Codes and Intervals 

Proportion Rejected

Distribution Test N 10% 5% 1%

Gamma Anderson-Darling 142,165 0.1666 0.1000 0.0322

Gamma Cramer-von Mises 142,165 0.1579 0.0929 0.0280

Gamma Kolmogorov-Smirnov 142,165 0.1478 0.0834 0.0228

Inverse Gaussian Anderson-Darling 149,875 0.6353 0.5643 0.4168

Inverse Gaussian Cramer-von Mises 149,875 0.6264 0.5432 0.4123

Inverse Gaussian Kolmogorov-Smirnov 149,875 0.5850 0.5010 0.3459

Lognormal Anderson-Darling 149,875 0.5401 0.4521 0.3080

Lognormal Cramer-von Mises 149,875 0.5048 0.4180 0.2750

Lognormal Kolmogorov-Smirnov 149,875 0.4575 0.3568 0.0000

Normal Anderson-Darling 149,875 0.7214 0.6361 0.4651

Normal Cramer-von Mises 149,875 0.6738 0.5835 0.4117

Normal Kolmogorov-Smirnov 149,875 0.6055 0.4925 0.0000

Truncated Normal Cramer-von-Mises 149,886 0.1826 0.1084 0.0427

Truncated Normal Kolmogorov-Smirnov 149,886 0.0369 0.0304 0.0272

Weibull Anderson-Darling 149,875 0.3357 0.2479 0.0000

Weibull Cramer-von Mises 149,875 0.3063 0.2163 0.0000
78

Table 4-4 

Goodness of Fit Results by Interval and Distribution

Proportion Rejected

Interval Distribution N 10% 5% 1%

625 Gamma 39,501 0.1686 0.1014 0.0327

625 InverseGaussian 40,875 0.6067 0.5232 0.3796

625 Lognormal 40,875 0.4878 0.4007 0.1885

625 Normal 40,875 0.7025 0.6153 0.3350

625 Truncated_Normal 27,252 0.1088 0.0620 0.0182

625 Weibull 27,250 0.3207 0.2352 0.0000

626 Gamma 39,348 0.1797 0.1089 0.0367

626 InverseGaussian 40,875 0.6025 0.5172 0.3621

626 Lognormal 40,875 0.4885 0.3897 0.1773

626 Normal 40,875 0.6803 0.5866 0.3091

626 Truncated_Normal 27,252 0.1168 0.0724 0.0265

626 Weibull 27,250 0.3507 0.2659 0.0000

627 Gamma 39,075 0.1424 0.0801 0.0225

627 InverseGaussian 40,875 0.5439 0.4607 0.3213

627 Lognormal 40,875 0.4380 0.3477 0.1580

627 Normal 40,875 0.6589 0.5670 0.2870

627 Truncated_Normal 27,252 0.1025 0.0611 0.0242

627 Weibull 27,250 0.3388 0.2462 0.0000

628 Gamma 38,916 0.1285 0.0686 0.0163

628 InverseGaussian 40,875 0.5051 0.4248 0.2889

628 Lognormal 40,875 0.4097 0.3226 0.1444

628 Normal 40,875 0.6537 0.5502 0.2734

628 Truncated_Normal 27,252 0.1188 0.0737 0.0349

628 Weibull 27,250 0.3657 0.2665 0.0000

629 Gamma 37,875 0.1269 0.0706 0.0198

629 InverseGaussian 40,875 0.5330 0.4451 0.3045

629 Lognormal 40,875 0.4335 0.3402 0.1525

629 Normal 40,875 0.6064 0.5085 0.2514

629 Truncated_Normal 27,252 0.1293 0.0897 0.0556

629 Weibull 27,250 0.3388 0.2406 0.0000

630 Gamma 38,946 0.1440 0.0825 0.0230

630 InverseGaussian 40,875 0.5707 0.4851 0.3289

630 Lognormal 40,875 0.4658 0.3700 0.1634

630 Normal 40,875 0.6024 0.4980 0.2363

630 Truncated_Normal 27,252 0.1091 0.0712 0.0430

630 Weibull 27,250 0.3444 0.2515 0.0000

631 Gamma 38,178 0.1395 0.0771 0.0199
79

Proportion Rejected

Interval Distribution N 10% 5% 1%

631 InverseGaussian 40,875 0.5816 0.4977 0.3502

631 Lognormal 40,875 0.4742 0.3794 0.1744

631 Normal 40,875 0.5983 0.4996 0.2467

631 Truncated_Normal 27,252 0.1196 0.0838 0.0549

631 Weibull 27,250 0.3300 0.2397 0.0000

632 Gamma 38,535 0.1548 0.0873 0.0227

632 InverseGaussian 40,875 0.6297 0.5492 0.4035

632 Lognormal 40,875 0.5169 0.4205 0.2004

632 Normal 40,875 0.6777 0.5804 0.2967

632 Truncated_Normal 27,252 0.1358 0.0918 0.0514

632 Weibull 27,250 0.3315 0.2472 0.0000

633 Gamma 38,919 0.1968 0.1211 0.0393

633 InverseGaussian 40,875 0.7822 0.7184 0.5705

633 Lognormal 40,875 0.6443 0.5545 0.2843

633 Normal 40,875 0.6862 0.5829 0.2929

633 Truncated_Normal 27,252 0.0873 0.0542 0.0286

633 Weibull 27,250 0.2284 0.1522 0.0000

634 Gamma 39,150 0.1747 0.1049 0.0342

634 InverseGaussian 40,875 0.7071 0.6401 0.5022

634 Lognormal 40,875 0.5763 0.4841 0.2446

634 Normal 40,875 0.7342 0.6428 0.3380

634 Truncated_Normal 27,252 0.0819 0.0461 0.0208

634 Weibull 27,250 0.2680 0.1793 0.0000

635 Gamma 38,052 0.1743 0.1097 0.0371

635 InverseGaussian 40,875 0.7087 0.6364 0.4967

635 Lognormal 40,875 0.5739 0.4893 0.2498

635 Normal 40,875 0.7355 0.6467 0.3481

635 Truncated_Normal 27,252 0.0976 0.0574 0.0264

635 Weibull 27,250 0.3141 0.2287 0.0000
80

We utilized standard maximum likelihood estimation techniques to estimate the truncated 

normal distribution for each grid code and interval combination. An important limitation of 

this approach merits discussion here. The truncated normal distribution can prove difficult to 

estimate by standard nonlinear estimation procedures when the variance of the relevant data 

is very large or when data are concentrated at levels close to the truncation point (zero in our 

case). Both conditions characterize very dry and high-risk grid locations. We were unable to 

estimate parameters to maximize the likelihood function for the truncated normal distribution 

in a few cases. Such grids typically have a very negative mean/scale parameter, which also 

leads to difficulties in rate estimation. We utilized rejection/acceptance sampling (onemillion replications) and in the cases of a very large in magnitude negative mean parameter, 

it is difficult to use rejection sampling methods because the relevant portion of the normal 

distribution that lies above the truncation point (zero) is very small. The lognormal 

distribution encounters similar problems in cases where a grid/interval has very low recorded 

rainfall and very high variance. In such a case, the distribution has an extreme mode close to 

zero and a very long right tail, reflecting the positive skew of the lognormal. 

We also believe that there is an error in the formula used to derive the BS/lognormal rates in 

the RMA rating program. The rating program uses the following coding 

std(log(index+0.0001)) as vol... 

d1=( log(1/coveragelevelpercent)+(vol**2)/2)/vol; 

 d2=d1-vol; 

 N_d1=cdf(“normal”,-d1,0,1);

 N_d2=cdf(“normal”,-d2,0,1);

 BS = N_d2 – N_d1/coveragelevelpercent; * black scholes rate ;

We have examined the formula carefully and do not believe the calculation is correct given 

the log-normal distribution assumption. Empirically, we compared the original (incorrect) 

formula from the developer and the BS rates calculated using a corrected formula. 

BS formulas for a put option: 

= KKee−rrrr (−dd2) − 0 (−dd1) (1)

dd1 = ln ( 0/KK) + (rr + σσ2/2)TT

σσ√TT (2)

dd2 = dd1 − σσ√TT (3).

Application to PRF index 
81

Assumptions: 

A1: K=c, where c=coverage level;

A2: r=0, the risk-free interest rate is zero, so no discounting; 

A3: T=1; 

A4: S0=1, the initial price for the index equals 1. 

With assumptions A1-A4, the formulas for the PRF index become 

= cc (−dd2) − (−dd1) (4)

dd1 = ln (1/cc) + (σσ2/2)

σσ (5)

dd2 = dd1 − σσ (6)

where σ is the standard deviation of the ln(index).

The equivalent of (4) used by the developer to calculate the BS rate is: 

= 1

cc �cc (−dd2) − (−dd1)� (7).

We believe the multiplication by 1/c in (7) is incorrect.

The comparison is based on the average BS rates for 2019 and all grids. The BS rates 

calculated using the corrected formula tend to be lower than the BS rates calculated using the 

original formula. The average difference between the two rates is from a high of 4.2 

percentage points for the 70% coverage level to a low of 2.1 percentage points for the 90% 

coverage level. Also, the corrected BS rates are very similar to the BR rates

As a further analysis, we randomly chose 500 grid codes from the collection of 13,626 total 

from the focus area illustrated in Figure 4-10. We calculated premium rates for coverage 

levels between 70-100 percent using each of the alternative distributions and the truncated 

normal. A summary of the average values of the shape and scale parameters is presented in 

Table 4-5. 
82

Table 4-5 

Average Values of ML Parameter Estimates

Standard

Distribution Threshold Scale Shape Mean Deviation

Gamma 0.0000 0.3208 3.9286 1.0000 0.5492

Inverse Gaussian 1.0000 --- 2.8412 1.0000 1.0155

Lognormal 0.0000 -0.1711 0.6283 1.0646 1.1474

Normal --- --- --- 1.0000 0.5333

Truncated Normal --- 0.6051 0.6771 --- ---

Weibull 0.0000 1.1205 2.0979 1.0011 0.5297

We utilized one-million replicates in a rejection sampling framework to determine rates 

based on each parametric distribution.10 Table 4-6 presents average rates across the entire 

sample of 500 grid codes (with 11 intervals each). Table 4-6 also includes RMA raw rates 

for the truncated normal (RMA’s version and the developer’s approximation). The results 

demonstrate that there is relative homogeneity among the alternative parametric and burn 

rates, at least at an aggregate level. The lognormal tends to generate rates that are 

considerably smaller than the BS rates. The inverse Gaussian distribution tends to produce 

the highest average rates. 

Average Values of Rates Across Selected 500 Grid Codes

Table 4-6 

Coverage Level

Distribution N 70% 75.00% 80.00% 85.00% 90.00% 100%

Black_Scholes 5500 0.1319 0.1500 0.1686 0.1875 0.2066 ---

Burn_Rate 5500 0.1082 0.1234 0.1393 0.1558 0.1729 ---

Dev_Truncated_Normal 5500 0.1247 0.1361 0.1480 0.1609 0.1743 ---

Gamma 5500 0.1102 0.1260 0.1424 0.1595 0.1769 0.2127

Gram Charlier 5500 0.1151 0.1279 0.1411 0.1556 0.1707 ---

Inverse Gaussian 5500 0.1547 0.1728 0.1913 0.2099 0.2286 0.2657

Lognormal 5500 0.1191 0.1366 0.1547 0.1731 0.1917 0.2291

Normal 5500 0.1387 0.1491 0.1603 0.1724 0.1852 0.2127

RMA_Truncated_Normal 5500 0.1248 0.1362 0.1482 0.1610 0.1744 ---

Truncated Normal 5387 0.1251 0.1382 0.1518 0.1660 0.1807 0.2113

10 For a discussion of rejection sampling, see P. W. Laud, P. Damien, and T. S. Shively, (2010) “Sampling Some 

Truncated Distributions Via Rejection Algorithms.” Communications in Statistics - Simulation and Computation,

Pages 1111-1121; and Marsaglia, George (1964). "Generating a variable from the tail of the normal distribution". 

Technometrics. 6 (1): 101–102.
83

Weibull 5500 0.1169 0.1314 0.1464 0.1619 0.1778 0.2106

We compared our rejection-based simulated rates to the two alternatives of the truncated 

normal embedded in the RMA rating program. As noted, we found the truncated normal to 

be unstable and difficult to fit by maximum likelihood methods in cases of high risk and long 

right tails. Such cases typically generated a mean value for the truncated normal that is very 

negative. This makes the effective coverage of the density to the right of the truncation point 

(zero) very small relative to the overall normal. Our rejection method rate estimates were 

compared to those generated by the RMA rating procedures. Table 4-7 below presents 

average values across the two alternative methods of rating with the truncated normal 

distribution. The rates are very close on average and the average differences are very close 

to zero. However, a consideration of differences across different levels of coverage does 

reveal modest differences at very high rates—a finding that likely reflects the substantial 

difficulties associated with fitting the truncated normal in very high-risk cases (Table 4-8). 

Comparison of Alternative Truncated Normal Rates 

Table 4-7 

RMA Rejection Method Mean

Coverage Level Truncated Normal Truncated Normal Difference

70% 0.1227 0.1251 -0.0024

75% 0.1340 0.1382 -0.0041

80% 0.1462 0.1518 -0.0057

85% 0.1590 0.1660 -0.0070

90% 0.1725 0.1807 -0.0082

100% --- 0.2113 ---
84

Table 4-8 

Truncated Normal Claim and Conditional Expected Indemnities

(Risk and Exposure) 

Probability of a Claim Expected Indemnity Conditional on a Claim

Distribution 70% 75.00% 80.00% 85.00% 90.00% 100% 70% 75.00% 80.00% 85.00% 90.00% 100%

Gamma 0.3258 0.3682 0.4108 0.4530 0.4944 0.5730 0.2244 0.2461 0.2688 0.2924 0.3169 0.3688

Inverse Gaussian 0.4047 0.4473 0.4885 0.5279 0.5652 0.6329 0.2330 0.2595 0.2870 0.3155 0.3449 0.4064

Lognormal 0.3595 0.4038 0.4470 0.4887 0.5284 0.6010 0.2169 0.2412 0.2666 0.2930 0.3205 0.3785

Normal 0.2784 0.3117 0.3469 0.3837 0.4218 0.5000 0.3338 0.3469 0.3608 0.3756 0.3912 0.4255

Truncated Normal 0.3041 0.3386 0.3744 0.4113 0.4489 0.5250 0.2777 0.2967 0.3161 0.3360 0.3565 0.3996

Weibull 0.3151 0.3525 0.3906 0.4292 0.4677 0.5438 0.2504 0.2711 0.2923 0.3142 0.3368 0.3842
85

Figure 4-10 shows the area of the U.S. where we conduct a more intensive comparison of rates.

Using this sample of grids, figures 4-11 through 4-13 are examples of the distributions fit using 

alternative fitted distributions. Figure 4-14 shows a histogram for a representative period that 

reflects the relatively small range of rainfall values often fit. 

Figure 4-10

Area of Focused Analysis of Premium Rates
86

Figure 4-11

Examples of Fitted Densities
87

Figure 4-12

Examples of Fitted Densities
88

Figure 4-13

Examples of Fitted Densities
89

Figure 4-14

Histogram of data from Grid 18083 and Interval 629. 

Figures 4-15 and 4-16 present rates derived from the truncated normal using the two 

alternative rating methods (our ML versions and those generated by the RMA rating 

program). The alternative rating methods track very closely at low to moderately high levels. 

However, a small but notable difference arises at higher rates, with our ML rejection 

sampling methods generating slightly higher rates. The differences are more notable at the 

higher 90 percent coverage level. The criteria for choosing one method over another are

unclear and the underlying reasons for the differences are likewise uncertain. As noted, this 

likely reflects the difficulties associated with working with a truncated normal distribution 

when the scale (mean) parameter is very negative (i.e., in high-risk situations). 
90

Figure 4-15

Seventy Percent Rate Comparison Rejection Method and RMA Truncated Normal

Figure 4-16

Ninety Percent Rate Comparison Rejection Method and RMA Truncated Normal 
91

Actuarial Recommendations 

Overall, this program is actuarially sound. Outside of a computation error in fitting the 

Black Scholes parameters, we find no significant shortcomings in the general approach used 

by RMA to estimate premium rates. Methods currently used to bound rates and to select the 

final rates from among the different rate estimates are ad hoc. We recommend that RMA 

consider the use of goodness-of-fit tests in the selection of the final parametric distribution 

used to estimate rates. Of course, rates derived from parametric distributions should be 

compared to empirical burn rates. In some cases with extremely high or low variance, 

convergence issues may make it difficult to adequately estimate parametric rates and thus 

any measure based on such rates needs a careful review. The truncated normal distribution 

is strongly supported in a majority of cases. Procedures currently used to spatially smooth 

rates are appropriate and we recommend no changes to these procedures.
92

Chapter 5 Evaluate the current program design 

Assessment of the frequency of payments

The assessment of the frequency of payments is conducted using the rainfall index data at the 

national level, including all grids. The assessment is performed for the period 2002-2018. 

There are eleven two-month intervals, J-F, F-M, M-A, A-M, M-J, J-J, J-A, A-S, S-O, O-N, 

and N-D. Producers can select up to six non-overlapping intervals. When producers select 

more than one interval, there are at least two different ways to calculate payment frequencies. 

The first way would be to calculate payment frequencies at the “producer level”. As an 

example, consider a producer who chooses five intervals. If at least one of the five intervals 

results in a payment, then the frequency of payment for this producer would be: 1/1 or 100 

percent. A second way to calculate payment frequencies would be at the “interval level”. 

Given that each interval is rated and indemnified independently of the other intervals when 

the producer chooses multiple intervals the producer is choosing different policies. 

Alternatively, when the producer chooses multiple intervals one can think as if the producer 

is choosing a single policy with multiple payments. For the example where the producer 

chooses five intervals, if one of the five intervals results in payment, then the frequency of 

payment for this producer would be 1/5 or 20 percent. 

Figure 5-1 shows the payment frequencies by interval and coverage level for the period 

2002-2018. Note that payment frequencies are very similar across the eleven intervals with 

only two intervals, J-F and F-M, where payment frequencies are slightly higher than the other 

intervals.

Figure 5-2 shows the payment frequencies by coverage level for the period 2002-2018. 

Payment frequencies increase with the coverage level.

Figures 5-3 and 5-4 show the payment frequencies for two combinations of the eleven 

intervals. The first combination consists of six non-overlapping two-month intervals, J-F, MA, M-J, J-A, S-O, and N-D. This combination is referred to as "ODD" (the first month of 

each interval is odd). The second combination consists of five non-overlapping two-month 

intervals, F-M, A-M, J-J, A-S, and O-N referred to as "EVEN".

Figure 5-3 shows the payment frequencies calculated at the “producer level”. Note that if at 

least one of the intervals in the combination results in a payment then the entire combination 

of five or six intervals also results in payment, and the frequency of payment for this 

producer would be 1/1 or 100 percent.
93

Figure 5-4 shows the payment frequencies calculated at the “interval level”. The frequency

of payment for each combination is calculated by dividing the number of intervals in the 

combination that result in a payment by the total number of intervals in the combination. 

Payment frequency was also assessed for three-month intervals. The three-month intervals 

considered were J-F-M, F-M-A, M-A-M, A-M-J, M-J-J, J-J-A, J-A-S, A-S-O, S-O-N, and ON-D.

Figure 5-5 shows the payment frequencies by three-month intervals and coverage level for 

the period 2002-2018. Note that payment frequencies for the two early in the year intervals 

J-F-M and F-M-A are again slightly higher than the other intervals. 

Figure 5-6 shows the payment frequencies for three combinations of the ten 3-month 

intervals. The first combination consists of four non-overlapping three-month intervals, J-FM, A-M-J, J-A-S, and O-N-D. This combination is referred to as "1st 3-Month". The second 

combination consists of three non-overlapping three-month intervals, F-M-A, M-J-J, and AS-O and is referred to as "2nd 3-Month". The third combination consists of three nonoverlapping three-month intervals, M-A-M, J-J-A, and S-O-N and is referred to as "3rd 3-

Month ". Figure 5-6 shows the payment frequencies calculated at the “producer level”. Note 

again that if at least one of the intervals in the combination results in a payment then the 

entire combination of five or six intervals also results in payment, and the frequency of 

payment for this producer would be: 1/1 or 100 percent.

Results of Figure 5-6 show that payment frequencies for the combination "1st 3-Month" are 

much higher than the payment frequencies for the other two combinations, "2nd 3-Month" 

and "3rd 3-Month". For example, for coverage level, 90 percent payment frequency for the 

"1st 3-Month" combination is 10 percentage points higher than payment frequency for the 

other two combinations. For coverage level, 70 percent the difference is about 13 percentage 

points. Note that combinations "2nd 3-Month" and "3rd 3-Month" do not include the months 

of January and December. 

Figure 5-7 shows the payment frequencies for the three-month intervals by coverage level for 

the period 2002-2018. Payment frequencies increase with the coverage level.

A comparison of Figures 5-1 and 5-5 indicates a tendency for the lower frequency of 

payments for the three-month intervals compared to the two-month intervals. A more direct 

comparison of the frequency of payments between the two- and three-month intervals is 

provided by comparing Figures 5-2 and 5-7. The frequency of payments for each coverage 

level for the three-month intervals, as shown in Figure 5-7, is lower than the respective 
94

frequency of payments for the two-month intervals shown in Figure 5-2. For example, the 

frequency of payments for the 90% coverage level is 42.5% for the three-month intervals 

versus 46.1% for the two-month intervals. Similarly, the frequency of payments for the 85% 

coverage level is 37.6% for the three-month intervals versus 41.8% for the two-month 

intervals.

A combination of lowering the highest coverage level and/or the replacement of the twomonth intervals with the three-month intervals would result in a lower frequency of small 

payments. For example, using two-month intervals but lowering the highest coverage level

from 90% to 80% would lower the highest frequency of payments from 46.1% to 37.6%. 

Alternatively, replacing the two-month intervals with the three-month intervals and keeping 

the highest coverage level the same at 90% would lower the highest frequency of payments 

from 46.1% to 42.5%. As another alternative, a combination of lowering the highest 

coverage level from 90% to 85% and replacing the two-month intervals with the three-month 

intervals would lower the highest frequency of payments from 46.1% to 37.6%. 
95

Figure 5.1. Payment Frequencies by Two-Month Interval and Coverage Level 2002-2018 

Figure 5.2. Payment Frequencies by Coverage Level for all Two-Month Intervals 2002-2018 

0

0.1

0.2

0.3

0.4

0.5

0.6

0.70.80.9

0.750.85

0.70.80.9

0.750.85

0.70.80.9

0.750.85

0.70.80.9

0.750.85

0.70.80.9

0.750.85

0.70.80.9

1 J-F 2-F-M 3 M-A 4 A-M 5 M-J 6 J-J 7 J-A 8 A-S 9 S-O 10 O-N 11 N-D

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.7 0.75 0.8 0.85 0.9
96

Figure 5.3. Payment Frequencies by Combinations of Two-Month Intervals and Coverage Level 

2002-2018 (Frequencies are calculated at the “producer level” – see text for definition)

Figure 5.4. Payment Frequencies by Combinations of Intervals and Coverage Level 2002-2018 

(Frequencies are calculated at the “interval level” – see text for definition)

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0.7 0.75 0.8 0.85 0.9 0.7 0.75 0.8 0.85 0.9

EVEN ODD

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0.5

0.7 0.75 0.8 0.85 0.9 0.7 0.75 0.8 0.85 0.9

EVEN ODD
97

Figure 5.5. Payment Frequencies by Three-Month Interval and Coverage Level 2002-2018 

Figure 5.6. Payment Frequencies by Combinations of Three-Month Intervals and Coverage 

Level 2002-2018 (Frequencies are calculated at the “producer level” – see text for definition) 
98

Figure 5.7. Payment Frequencies by Coverage Level for all Three-Month Intervals 2002-2018 
99

Intervals contributing to forage production

Producers are given latitude to insure any period during the year. Given that some regions 

may have a mix of cool and warm-season grasses, defining a set period for a growing season 

may be difficult. Also, producers in arid regions may believe that pre-growing season 

rainfall is critical for growing season forage production. However, the Agrilytica report 

(2014 P 3.) states “While many producers allocate insurance to intervals that have the 

highest production risk, some select the intervals they think will yield the highest potential 

pay-out (based on several criteria). Others select all or several intervals to maximize the 

chances of an indemnity. For these producers, the interval selection incentives conflict

with RMA’s view of the risk management objectives of the plans. In Texas, the uniform

spreading of liability is not consistent with historical rainfall averages, which are much

higher in summer months.” 

As noted in the literature review, Diersen et al. (2015) suggest that the most risk efficient 

intervals are May-June and July-August and these choices are most consistent with the desire 

to have payments that offset the highest expected forage risk. Similarly, Westerhold et al. 

(2018) also find that intervals that coincide with the actual growing season in Nebraska are 

the ones where PRF provides the largest risk reductions. They go on to suggest dropping 

intervals in the PRF contract that do not coincide with the growing season since these 

intervals tend to be used as an income maximizing strategy rather than risk reduction. 

Assessment of the relationship between hay yields and weather variables

Data for this part of the analysis consists of alfalfa other (excluding alfalfa) hay yields 

(ton/acre) from NASS, precipitation (mm), temperature (degree C), and Palmer Drought 

Severity Index (PDSI) (generally between -2 and 2) data. Data are observed annually at the 

state level. As an alternative to state-level data, county-level data are used to distinguish 

between different parts within a state that use irrigated or non-irrigated practice.

The dependent variable for this part of the analysis consists of alfalfa hay yield and other 

(excluding alfalfa) hay yield. The discussion here is for the case of other (excluding alfalfa) 

hay yield. Findings are similar for the case of the alfalfa hay yield. The dependent variable 

(hay yield) was modeled as a function of two sets of independent variables. The first set 

includes precipitation and temperature while the second set consists of PDSI. A trend 

variable is also included in both sets. 

Several issues were investigated:
100

1. What is the effect of the monthly precipitation, temperature, and PDSI variables on hay 

yields? 

2. What is the effect of the neighboring states' aggregate precipitation, temperature, and 

PDSI variables on the hay prices of a target state?

3. Is there a nonlinear (quadratic) relationship between precipitation, temperature, and PDSI 

and hay prices? 

The results for each of these issues are discussed below.

1. What is the effect of the monthly precipitation, temperature, and PDSI variables on hay 

yields? 

Two sets of regressions were estimated to address the first issue. First, hay yields were 

regressed against 12 monthly variables of precipitation and temperature. Second, monthly 

variables of precipitation and temperature were aggregated into two 6-month periods, one 

before the growing season from previous October to March and the other during the growing 

season from April to September. A trend variable was also added in both sets of regressions. 

The same analysis was repeated to investigate the relationship between hay yields and PDSI.

Some general notation description for all the tables is provided here. P indicates 

precipitation, T indicates temperature, and PDSI indicates the Palmer Drought Severity 

Index. The numbers in parenthesis following P, T, and PDSI indicate lags, for example, P(3) 

indicates the value of precipitation lagged by three months. The numbers without parenthesis 

following P, T, and PDSI indicate the calendar month, for example, P3 indicates the value of 

precipitation for March. X^2 indicates the square term of the variable X while NB_X 

indicates the aggregate value from the neighboring states for the variable X. 

The results of the stepwise regression of the relationship between hay yields and precipitation 

and temperature are reported in Table 5.1 for the case of monthly variables and Table 5.2 for 

the case of the two 6-month periods, respectively. The results of the relationship between 

hay yields and PDSI are reported in Table 5.3 and Table 5.4, respectively. 

Table 5.5 presents the extends the analysis to include the effect of precipitation and 

temperature variables from the neighboring states. Table 5.6 presents similar results to table 

5.5 for PDSI variables.

The results of Table 5.1 show that the maximum number of significant monthly variables for 

precipitation varies from zero to seven. For temperature the number of significant monthly 

variables varies from zero to six. Additionally, all monthly variables for both precipitation 

and temperature have a significant effect on hay yield for at least one state. Results of Table 

5.1 also show that precipitation, temperature, and a trend variable explain from a low of 26% 

for the state of MI to a high of 97% for MT of the variation in hay yields. 

The results of Table 5.3 show that the maximum number of monthly variables for PDSI 
101

varies from zero to four. Additionally, all monthly variables for PDSI, except for March, 

have a significant effect on hay yield for at least one state. Results of Table 5.3 show PDSI 

explains from a low of 0% for the states of IA, MI, and OH to a high of 84% for ND and CO 

of the variation in hay yields. 

Table 5.2 presents the results of the regression of the hay yield on monthly precipitation and 

temperature variables aggregated into a prior to – and during the growing season. Table 5.4 

presents the results of the similar regression of the hay yield on the aggregated monthly PDSI 

variables. Results of Table 5.2 show that while for a few states precipitation before the 

growing season has a significant effect on hay yield, for the majority of states (21 out of 29 

states), it is the precipitation during the growing season that significantly affects hay yield. 

This finding indicates that restricting interval selection to only during the growing season 

should not negatively affect the risk management offered by the program.

Results of Table 5.4 similarly show that while for a few states PDSI before the growing 

season has a significant effect on hay yield, for the majority of states (21 out of 29 states), it 

is the PDSI during the growing season that significantly affects hay yield. This finding again 

indicates that restricting interval selection to only during the growing season should not 

negatively affect the risk management offered by the program.

As noted earlier, to distinguish between different parts within a state that use irrigated or nonirrigated practice, county-level data are used to derive state-level yield data as an alternative 

to the all-practice state-level data. NASS reports yield data for a limited number of counties. 

Agriculture Census data, available from NASS, were used to identify whether a county 

within a state is under a dominantly irrigated or non-irrigated practice. If the percentage of 

irrigated acres in hay production in a county is more than 50 percent of total acres in hay 

production, the county is designated as an irrigated county. Otherwise, the county is 

designated as the non-irrigated county. State-level yields for irrigated and non-irrigated 

practice were then calculated as a weighted average of the county yields with acreage being 

used as weights. 

The results of the analysis using the yield data obtained as above are reported in Tables 5.7 

through 5.12. The results from Tables 5.7 – 5.12 provide a similar picture as the earlier results 

using state-level data. While some differences were found in the relationship between yield 

and weather variables like precipitation, temperature, and PDSI for the irrigated versus nonirrigated practices within a state, these differences cannot be generalized across states.

Finally, we did the same analysis at the county level for 1,700 counties to further test whether 

the findings use state-level data are consistent at the county level. The story of Table 5.1 

repeats here. Only 4 counties (0.24%) have 8 months of precipitation effect as 

significant. Another 17 counties (1%) have 7 months of significant precipitation effect. 41 

counties (2.41%) have 6 months of significant precipitation effect. The rest of the counties, 
102

1,638 of them (96.35%) have only 5 or fewer months of significant precipitation effect. For 

the Western states (CA, AZ, NM, and NV), 47 of the 56 counties (83.93%) have only 3 or 

fewer months of significant precipitation effect, or 39 of the 56 counties (69.64%) have only 

2 or fewer months of significant precipitation effect. 

The results for the case of the alfalfa hay yield are presented in tables 5-13 – 5.18. Findings 

for the case of the alfalfa hay yield are similar to findings for the case of other (excluding 

alfalfa) hay yield discussed above. 

We believe this provides strong evidence of two things. First, there is little evidence in the 

forage literature or our analysis that producers suffer from significant rainfall risk in more 

than eight months per year. However, because production systems sometimes vary even 

within a county, we believe producers may need the flexibility to choose the periods that best 

fit their operation and reduce the basis risk for their farm. Ultimately, we recommend 

increasing the minimum percentage of value in any one index interval to 25 percent if twomonth intervals are used or 33 percent if three-month intervals are used. This will avoid the 

paperwork of additional indices and will require producers to focus participation in periods 

that most affect production. 
103

Table 5-1. Results of the stepwise regression of the hay (excluding alfalfa) yield on monthly precipitation and temperature

Prod_Pract State Constant Trend P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 P_max T_max Rsq

All AZ 10.582*** 0.032*** 0.009* -0.008*** -0.248*** -0.035** 2 2 0.71

All CA 3.955*** 0.028*** -0.001* -0.021** -0.009* -0.098*** 3 1 0.76

All CO 3.600*** 0.007*** 0.005*** 0.048*** -0.037** -0.103*** 1 3 0.64

All ID 1.869*** 0.012*** -0.002** 0.003*** 0.003** 0.009*** -0.047*** 0.029** 0.038*** 4 3 0.74

All IL 1.384*** 0.008** 0.003*** 0.003** 0.002* 3 0 0.5

All IA 3.670*** 0.003*** -0.002* 0.020* 0.042** -0.085*** 2 3 0.47

All KS 4.526*** 0.001** 0.002*** 0.001** 0.020*** -0.023*** -0.067***-0.033** -0.023* -0.029*** 3 6 0.86

All KY 1.172** 0.001* 0.001* 0.004*** 0.002** 0.002*** 0.026** 0.046*** -0.041* 5 3 0.74

All MI 3.119*** -0.005** 0.003* -0.057* 2 1 0.26

All MN 1.695*** -0.012*** 0.003** -0.026* 0.051** 1 2 0.39

All MO 2.729*** 0.002*** 0.002*** 0.003*** 0.001** 0.001* 0.030*** -0.047*** -0.056*** 0.014** 5 4 0.8

All MT 0.775*** 0.008*** 0.004*** 0.002** 0.007*** 3 0 0.7

All NE -0.299 0.010*** 0.003*** 0.002*** 0.001* 0.003** 0.023** 0.024** -0.023*** 4 3 0.85

All NV 1.777*** 0.019*** 0.006*** -0.036* 0.040** 1 2 0.69

All NM 2.265** 0.018*** 0.051** -0.146***0.106*** -0.067*** 0 4 0.62

All NY 3.266*** -0.005** 0.001* -0.071*** 1 1 0.45

All ND 0.922*** 0.009*** 0.011*** 0.003*** 0.004*** 0.002** -0.004*** 0.004*** -0.030* 6 1 0.84

All OH 4.862*** 0.002* -0.003*** 0.002** 0.055*** -0.075*** -0.076*** -0.032***3 4 0.68

All OK 1.527** 0.001* 0.003*** 0.001* -0.043*** -0.043** 0.038** 3 3 0.7

All OR 1.400*** 0.017*** 0.003*** 0.001* 0.001* 3 0 0.72

All PA 1.074*** -0.002* 0.003*** 0.003*** 0.002** 0.040* 4 1 0.6

All SD 0.293 0.010*** 0.008*** 0.003*** 0.002** 0.002*** 0.003* -0.015*** -0.020*** 0.029** 5 3 0.86

All TX 8.981*** 0.005*** -0.180*** -0.085* 1 2 0.59

All UT 2.555*** 0.013*** 0.003*** -0.001* 0.004*** 0.003*** -0.005***-0.020***-0.022** -0.059***0.025** -0.034** 5 5 0.87

All WI 2.062*** 0.005*** -0.034*** 1 1 0.3

Irrig CO 1.748*** 0.014*** 0.004* 0.006** 0.004*** 0.007*** -0.044* 4 1 0.83

Irrig MT 1.294*** 0.013*** 0.003** 0.003* -0.001** 0.004*** 0.001** -0.004*** 0.005*** -0.027*** -0.029*** 7 2 0.97

Non_Irrig CO 0.792** 0.002* 0.007*** 0.008*** -0.052* -0.029** 3 2 0.74

Non_Irrig MT 0.296** 0.006*** 0.002* 0.012*** 0.020** 3 1 0.75

Total 7 9 1 3 15 13 14 5 4 8 7 2 3 6 3 6 4 5 6 9 5 6 7 4
104

Table 5-2. Results of the regression of the hay (excluding alfalfa) yield on precipitation and temperature prior toand during the growing season

Prod_Pract State Constant Trend P_prior P_during T_prior T_during Rsq

All AZ 4.692** 0.030*** -0.001 0.001 -0.032 -0.045 0.41

All CA 3.04 0.038*** 0 0.001 -0.158* 0.029 0.68

All CO 1.464 0.008* 0.002 0.001 0.028 -0.045 0.36

All ID 1.908** 0.007** 0 0.002** 0.051 -0.035 0.42

All IL 1.711 0.006 -0.001 0.001** 0.004 0.006 0.35

All IA 2.613** -0.003 0 0.001 0.002 -0.036 0.09

All KS 3.101*** -0.003 0 0.001*** -0.004 -0.092** 0.69

All KY 2.561* 0.006 0 0.001*** 0.039 -0.07 0.46

All MI 3.171** -0.002 -0.001 0.001 0.003 -0.074 0.12

All MN 2.005** -0.012*** 0.001 0.001* 0.002 -0.026 0.28

All MO 2.579*** 0.004 0 0.001*** 0.046** -0.089** 0.57

All MT 0.448 0.007** 0.001 0.002*** 0.019 0.017 0.52

All NE -0.338 0.007*** 0.001 0.002*** 0.005 0.04 0.69

All NV 1.731* 0.016*** 0.001 0 0.057 -0.044 0.61

All NM 2.423 0.016*** 0 0 -0.069 -0.014 0.44

All NY 2.945*** -0.006* 0 0.001* 0.017 -0.076 0.31

All ND 0.248 0.007** 0.002** 0.002*** -0.002 0.007 0.59

All OH 4.688*** -0.004 0 0.001* 0.042 -0.150** 0.33

All OK 4.124*** 0.002 0.001*** 0.001** -0.013 -0.135*** 0.56

All OR 0.715 0.018*** 0.000** 0.001* -0.012 0.04 0.67

All PA 1.905 0.007 0 0.001*** -0.011 -0.025 0.34

All SD 0.928*** 0.010*** 0.001* 0.002*** -0.018 -0.029** 0.66

All TX 4.168* -0.010* 0.001* 0.002** 0.083* -0.157 0.62

All UT 2.841*** 0.011*** 0 0.001 -0.017 -0.059* 0.58

All WI 1.230* -0.016*** 0.001 0.002*** -0.001 -0.025 0.42

Irrig CO -0.828 0.012** 0.003*** 0.003*** -0.055 0.08 0.69

Irrig MT 0.763 0.017*** 0.001 0.001* -0.016 0.018 0.53

Non_Irrig CO -0.641 -0.003 0.001 0.003** -0.116* 0.063 0.43

Non_Irrig MT -0.223 0.006 0.001 0.003*** 0.034 0.017 0.49
105

Table 5-3. Results of the stepwise regression of the hay (excluding alfalfa) yield on monthly PDSI

Prod_Pract State Constant Trend PDSI1 PDSI2 PDSI3 PDSI4 PDSI5 PDSI6 PDSI7 PDSI8 PDSI9 PDSI10 PDSI11 PDSI12 PDSI_max Rsq

All AZ 3.486*** 0.028*** 0 0.36

All CA 2.348*** 0.032*** 0 0.62

All CO 1.429*** 0.010*** 0.055*** 1 0.34

All ID 1.861*** 0.010*** -0.178* 0.216** 2 0.45

All IL 2.103*** 0.007** -0.220*** 0.205*** -0.147* 0.205** 4 0.57

All IA 2.226*** 0 0

All KS 1.802*** -0.003* -0.041*** 0.089*** 2 0.59

All KY 2.071*** -0.105** 0.085* 0.068*** 3 0.44

All MI 2.003*** 0 0

All MN 2.149*** -0.014*** 0.072*** 1 0.48

All MO 1.809*** 0.072*** -0.028* 2 0.37

All MT 1.326*** 0.008*** -0.068*** 0.106*** 2 0.6

All NE 1.127*** 0.009*** 0.043*** 1 0.62

All NV 1.264*** 0.018*** 0.029** 1 0.6

All NM 1.703*** 0.012*** 0.072** -0.091*** 2 0.51

All NY 1.980*** -0.005* -0.021** 1 0.27

All ND 1.389*** -0.400*** 0.157*** 0.336** 3 0.84

All OH 2.253*** 0 0

All OK 1.595*** 0.069*** -0.033** 2 0.38

All OR 1.716*** 0.019*** 0.029** 1 0.66

All PA 2.040*** -0.172*** 0.145** 0.101*** 3 0.51

All SD 1.195*** 0.009*** 0.115*** -0.051*** 2 0.78

All TX 2.043*** -0.589*** 0.679*** -0.071* 3 0.56

All UT 1.899*** 0.011*** -0.111** 0.121*** 2 0.59

All WI 2.343*** -0.021*** 0.129*** 1 0.46

Irrig CO 1.556*** 0.020*** 0.054** -0.149*** 0.173*** 3 0.84

Irrig MT 1.627*** 0.018*** -0.071** 0.101*** 2 0.6

Non_Irrig CO 1.287*** 0.060* -0.184*** 0.192*** 3 0.57

Non_Irrig MT 0.949*** 0.009** -0.095*** 0.135*** 2 0.54

Total 1 1 0 2 9 9 11 6 4 2 1 3
106

Table 5-4. Results of the regression of the hay (excluding alfalfa) yield on PDSI before- and during the growing season

Prod_Pract State Constant Trend PDSI_prior PDSI_during Rsq

All AZ 3.463*** 0.030*** 0.003 0.008 0.36

All CA 2.300*** 0.035*** -0.034 0.061 0.65

All CO 1.427*** 0.010*** -0.003 0.060** 0.31

All ID 1.913*** 0.008*** -0.008 0.054** 0.39

All IL 2.118*** 0.007* -0.041 0.085** 0.31

All IA 2.251*** -0.002 -0.034 0.048 0.05

All KS 1.758*** -0.002 -0.070*** 0.112*** 0.48

All KY 1.923*** 0.008** -0.042 0.064** 0.33

All MI 2.100*** -0.005 -0.059 0.063 0.07

All MN 2.149*** -0.014*** -0.02 0.098*** 0.49

All MO 1.733*** 0.004 -0.050** 0.088*** 0.37

All MT 1.329*** 0.008*** -0.02 0.056*** 0.47

All NE 1.126*** 0.008*** -0.032 0.073*** 0.63

All NV 1.274*** 0.018*** -0.01 0.037 0.59

All NM 1.737*** 0.012*** -0.023 0.009 0.38

All NY 2.001*** -0.006** -0.036** 0.025 0.29

All ND 1.321*** 0.004 -0.068*** 0.155*** 0.75

All OH 2.395*** -0.007 -0.083* 0.090* 0.14

All OK 1.564*** 0.001 -0.039* 0.083*** 0.33

All OR 1.709*** 0.019*** 0.003 0.026 0.65

All PA 1.916*** 0.008** -0.044 0.105*** 0.37

All SD 1.203*** 0.008*** -0.066*** 0.132*** 0.77

All TX 2.220*** -0.009** -0.173*** 0.211*** 0.52

All UT 1.925*** 0.009*** -0.035 0.047** 0.5

All WI 2.351*** -0.022*** -0.015 0.153*** 0.44

Irrig CO 1.550*** 0.019*** 0.012 0.072*** 0.66

Irrig MT 1.632*** 0.018*** -0.033 0.060** 0.49

Non_Irrig CO 1.264*** 0 0.008 0.065* 0.36

Non_Irrig MT 0.954*** 0.009* -0.042 0.081** 0.33
107

Table 5-5. Results of the nonlinear regression of the hay (excluding alfalfa) yield on precipitation and temperature and neighboring states

Prod_Pract State Constant Trend P_prior P_during T_prior T_during P_prior^2 P_during^2 T_prior^2 T_during^2 NB_P NB_T Rsq

All AZ -16.34 0.037*** 0.003 -0.038** 0.209 1.980* 0 0.000** -0.007 -0.049* 0.001 0.110* 0.61

All CA -86.97* 0.040*** 0.004** -0.011* 0.663 8.670* 0.000** 0.000** -0.041 -0.219* -0.001 0.028 0.82

All CO -10.25 0.008* 0.02 -0.004 0.02 1.479 0 0 -0.008 -0.052 0.001 -0.026 0.44

All ID 3.451 0.009*** -0.004 -0.015** 0.057 0.11 0 0.000** 0.009 -0.005 -0.001 -0.002 0.57

All IL 24.771 0.008 -0.001 0.004 0.073 -2.461 0 0 -0.012 0.063 0 0.006 0.41

All IA -6.828 -0.004 -0.001 0.010*** -0.003 0.586 0 -0.000*** -0.005 -0.016 0.001 0.024 0.66

All KS 12.923 -0.003 -0.002 0.002 0.034 -1.076 0 0 -0.003 0.024 0.001 0.003 0.72

All KY -5.756 0.009* -0.002 0.004 0.293 0.611 0 0 -0.021 -0.016 -0.001 -0.012 0.52

All MI 9.528 -0.002 0.012 0.030** 0.006 -2.262 0 -0.000** 0.006 0.074 -0.001 0.052 0.3

All MN -14.72 -0.015*** 0.002 -0.003 -0.024 2.232 0 0 -0.003 -0.074 0.003* 0.014 0.44

All MO 0.709 0.003 0.003 0.005** 0.008 -0.107 0 0.000* 0.004 0 0 0.013 0.66

All MT -0.708 0.006** 0 0.001 -0.017 0.204 0 0 -0.01 -0.007 0.001 0.019 0.55

All NE -1.67 0.007** 0 0.001 0.039 0.196 0 0 -0.012 -0.004 0 0 0.71

All NV -13.01 0.015*** -0.004 0.003 0.011 1.87 0 0 0.008 -0.058 0.001 -0.050** 0.78

All NM 7.878 0.015*** 0.002 -0.006 0.343 -0.67 0 0 -0.034 0.018 -0.001 -0.022 0.52

All NY -22.27* -0.003 -0.001 0 0.026 3.148* 0 0 -0.002 -0.103* -0.003***0.036* 0.61

All ND -2.499 0.004 -0.002 0.009* 0.133 0.232 0 0 0.014 -0.007 0.002 0.016 0.7

All OH -2.744 -0.006 0.003 0.011** 0.127 0.158 0 -0.000** -0.018 -0.006 -0.002 0.012 0.52

All OK -19.45 0.002 0.003 0.005*** -0.267 1.761 0 0.000** 0.015 -0.04 0.001 0.03 0.74

All OR -7.506 0.018*** 0.002 -0.001 -0.102 1.25 0 0 0.016 -0.043 -0.001 -0.018 0.7

All PA -0.195 0.001 0.014** 0.003 -0.073 -0.263 -0.000** 0 0.011 0.006 0.003** 0.011 0.56

All SD -0.396 0.008** 0.003 0.002 -0.01 0.055 0 0 0.003 -0.002 0.002 0.028 0.72

All TX 49.825 -0.016** 0.006* 0.001 -2.416** -2.608 -0.000* 0 0.101** 0.05 -0.001 -0.055 0.74

All UT 1.479 0.010*** -0.003 0.002 -0.017 0.107 0 0 -0.004 -0.005 0.003 0.018 0.64

All WI -3.785 -0.018*** 0 0.007 0.061 0.422 0 0 0.008 -0.016 0.001 0.102** 0.64

Irrig CO -7.177 0.008 0.030* 0.001 0.034 0.813 -0.000* 0 -0.064 -0.026 0 -0.078* 0.81

Irrig MT -5.824 0.016*** -0.015 -0.004 -0.086 1.38 0 0 -0.027 -0.052 0.001 -0.011 0.61

Non_Irrig CO -17.64 -0.007 0.054** -0.009 -0.06 2.185 -0.000** 0 -0.041 -0.074 0 -0.102* 0.69

Non_Irrig MT -5.356 0.006 -0.009 0 0.021 0.971 0 0 -0.008 -0.036 0.002 0.016 0.55
108

Table 5-6. Results of the nonlinear regression of the hay (excluding alfalfa) yield on PDSI and neighboring states

Prod_Pract State Constant Trend PDSI_prior PDSI_during PDSI_prior^2 PDSI_during^2 NB_PDSI Rsq

All AZ 3.352*** 0.008*** -0.023 0.066 0.003 0.021 -0.041 0.4

All CA 2.353*** 0.000*** -0.025 0.061 -0.012 -0.003 -0.005 0.68

All CO 1.529*** 0.009*** -0.009 0.027 -0.003 -0.006 0.064** 0.45

All ID 1.854*** 0.003*** -0.017 0.041 -0.005 0.011 0.035 0.44

All IL 2.126*** 0.077*** -0.04 0.077* 0.013 -0.02 0.01 0.35

All IA 2.350*** 0.303*** -0.032 -0.016 0.009 -0.023** 0.084** 0.27

All KS 1.704*** 0.761*** -0.059*** 0.060*** 0.011** -0.005 0.069*** 0.73

All KY 1.944*** 0.058*** -0.059** 0.087*** 0.020* -0.024** 0.003 0.43

All MI 2.123*** 0.199*** -0.052 0.026 0.021 -0.02 0.068 0.21

All MN 2.125*** 0.000*** -0.031 0.090*** 0.026*** -0.011 0.027 0.65

All MO 1.710*** 0.205*** -0.059** 0.098*** 0.011 -0.007 -0.002 0.42

All MT 1.334*** 0.001*** -0.018 0.048** 0.006 -0.006 0.013 0.5

All NE 1.130*** 0.000*** -0.031 0.068** -0.002 0 0.007 0.64

All NV 1.265*** 0.000*** -0.021 0.008 -0.002 -0.003 0.052** 0.65

All NM 1.735*** 0.003*** -0.024 0.02 -0.001 -0.001 -0.021 0.39

All NY 2.042*** 0.050*** -0.041** 0.023 -0.008 -0.001 0.008 0.35

All ND 1.386*** 0.052*** -0.087*** 0.186*** -0.003 -0.014** -0.034** 0.82

All OH 2.386*** 0.278*** -0.098** 0.098* 0.023** -0.027* -0.024 0.27

All OK 1.629*** 0.887*** -0.069*** 0.099*** 0.017** -0.028*** 0.03 0.57

All OR 1.657*** 0.000*** 0.01 -0.007 0.014* -0.007 0.036 0.73

All PA 2.050*** 0.484*** -0.060** 0.064 0 -0.02 0.045 0.47

All SD 1.222*** 0.000*** -0.048** 0.122*** 0.014** -0.018** -0.011 0.81

All TX 2.211*** 0.085*** -0.183*** 0.206*** 0.012 -0.005 0.028 0.54

All UT 1.891*** 0.000*** -0.015 0.02 0.006 -0.004 0.021 0.55

All WI 2.359*** 0.000*** -0.026 0.162** 0.045** -0.047** 0.007 0.54

Irrig CO 1.543*** 0.000*** 0.01 0.072** 0.006 -0.003 0.002 0.68

Irrig MT 1.614*** 0.002*** -0.038 0.066 0.003 0.01 0.007 0.57

Non_Irrig CO 1.312*** 0.982*** -0.001 0.038 -0.006 -0.002 0.044 0.41

Non_Irrig MT 0.960*** 0.101*** -0.037 0.056 0.005 -0.004 0.025 0.35
109

Table 5-7. Results of the stepwise regression of the hay (excluding alfalfa) yield on monthly precipitation and temperature using county-level data

Prod_Pract Irrigated State ConstantTrend P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 P_max T_max Rsq

All No AL 3.717*** 0.024*** . . . . . 0.002*** 0.001** . . . 0.002*** . -0.035***-0.030* . 0.055** . . . -0.111***. . . . 3 4 0.89

All No AZ 13.343** . -0.009***. . . . . . . . . . . . . 0.111*** . . . . -0.367***. . . -0.131* 1 3 0.67

All No IL 2.227*** . . . . . 0.002** . . . . . . . . . . . . . . . . . -0.039** . 1 1 0.3

All No KS 3.851*** . . . . . 0.002*** . . . 0.002** . . . . 0.019** -0.018* . . . -0.085***. . . -0.025** . 2 4 0.65

All No KY 2.108*** 0.011*** . . . . . 0.003*** . 0.003*** . . . . . 0.025** . . . . . . -0.044* . . . 2 2 0.7

All No MN 1.875*** -0.013***. . . . . . 0.003** . . . . . . . . . . . . . . . . . 1 0 0.41

All No NE 0.500*** 0.011*** . . . . 0.002*** 0.002*** . . 0.001* . . . -0.016***0.015*** . . 0.014* . . . . . -0.021***. 3 4 0.89

All No NV 1.354*** 0.058*** . . . -0.009* . . . . . . . 0.006* . . . . . . . . . . -0.072** 0.127**2 2 0.83

All No NJ 5.789*** -0.013***. . -0.001** . . . . . . . . 0.001*** . . . . -0.029** -0.079***. -0.080***. 0.021 . . 2 4 0.87

All No NM -0.104 0.031*** . 0.022** 0.024** . . . . . . . . . . . . . . . . . . . 0.147** . 2 1 0.41

All No NY 2.459*** -0.010***. . . . 0.001 . . . . . . . . . . -0.034** 0.035** . . -0.055** . 0.038** . . 1 4 0.62

All No ND 0.391*** 0.009*** . 0.009*** . 0.004*** 0.003*** 0.003*** 0.002*** -0.002* . 0.004*** . . . . . . . . . . . . . . 7 0 0.86

All No OK 3.324*** . . . . 0.002** 0.001*** 0.002*** . . . . . 0.001* -0.035***. . . . -0.034* . -0.057***0.035** -0.031* . . 4 5 0.8

All No OR 1.930*** 0.006** . . . -0.002* 0.004*** . . . . . . 0.001** . . . . . . . . . . -0.027* . 3 1 0.44

All No PA 2.093*** . . . . . . 0.003*** 0.002** . . 0.003*** . . . . . . . -0.058* . . . . 0.052** . 3 2 0.58

All No SD 2.117*** . 0.008** . . 0.006*** 0.004*** 0.002*** . 0.004*** . . . . . . . . . -0.055***-0.043***. . 0.023** . . 5 3 0.93

All No TN 3.054*** . . . . 0.001* 0.001** 0.001* . 0.004*** . . . -0.002***. . . . . . . -0.070***. . 0.036*** . 5 2 0.81

All No UT 2.367*** . . 0.002*** . . . . 0.003** . . 0.004*** -0.004***-0.002** . . . -0.055***. . -0.030***. . 0.043*** 0.030*** . 5 4 0.92

All No VA 0.999*** . . . -0.003***0.004*** 0.002*** . 0.007*** . -0.001* . 0.002** . . . . . . . . . . . . . 6 0 0.81

All No WA 5.167*** . 0.003*** -0.003** . . . -0.012***. . . . . . . . . . . -0.149***. . . . . . 3 1 0.42

All No WV 2.873*** . . . 0.002* . . 0.003*** . . . . . . . . . . . . -0.072** . . . . . 2 1 0.35

All No WI 1.598*** -0.019***. . . . . 0.003** 0.004** . . . . . . . . . . . . . . . . . 2 0 0.46

All Yes AZ 4.927*** . . . . . . . . . . . . . . . . . . . . . . . . -0.187* 0 1 0.13

All Yes CO 2.254*** . . . . . . . . 0.005*** . 0.005*** -0.003** . . 0.049*** . . 0.043** . -0.068** . . . . . 3 3 0.6

All Yes KS -1.039 . . . . . . . 0.004** . . . . . . . . . . . . . 0.073 0.118** . . 1 2 0.35

All Yes MT 0.946*** 0.008*** . . 0.002* 0.003*** . 0.003*** 0.003*** . . . 0.005*** . . . . 0.035*** -0.035***. . . . -0.024***. . 5 3 0.85

All Yes NE 0.233 0.018*** . . . . 0.002* . . . . . . . . . . . . . . 0.046* . . -0.048***. 1 2 0.5

All Yes NV 2.066*** 0.022*** . . . -0.005** . . . . . . . . . . . -0.024* -0.038** . . . . . . 0.071**1 3 0.82

All Yes NM 1.783 0.015*** . . . . 0.003* . . . . . . . . . . . 0.074*** . -0.152***0.119*** . . -0.071***-0.057* 1 5 0.67

All Yes OR 1.245*** 0.021*** . . . . 0.005*** . . . . . . 0.002*** . . . . . . . . . . -0.036** . 2 1 0.72

All Yes UT 4.098*** 0.010*** . 0.003*** -0.002* . . 0.005** . . . . . . . . . . . . . -0.082***. -0.036** . . 3 2 0.78

All Yes WA 7.081*** 0.073*** . . . . . . . . . . . -0.004* . . . . . -0.240** . . . . . . 1 1 0.55

All Yes WY 0.701*** 0.006*** . . . 0.003* 0.003*** 0.003** . 0.006*** . . . . . . 0.024** . . . . . . . . . 4 1 0.71

Irrig Yes CO 2.746*** 0.016*** . . . . . . . . . 0.007*** . . . . . . . . -0.069** . . . . . 1 1 0.64

Irrig Yes MT 1.114*** 0.016*** . . . 0.005*** . . 0.004*** . . . 0.002* . . . -0.014** . -0.037***. . . 0.038*** . -0.015** . 3 4 0.93

Irrig Yes WY 1.652*** 0.011*** . . . . 0.002** 0.002* . 0.009*** . . . . . . 0.019 . . . . . -0.045***-0.037** . . 3 3 0.72

Non_Irrig Yes CO 2.701*** . . -0.013** . . . . . . -0.010** . . . . . . -0.107** . . . . . . . . 2 1 0.39

Non_Irrig Yes MT 1.041*** 0.003 0.004** . . 0.003** . 0.004*** 0.003*** . . . 0.010*** -0.005***. . . . . -0.037***. . . -0.025** -0.012** 0.019**6 4 0.94

Non_Irrig Yes WY 0.058 . . . . 0.005*** 0.003** 0.007*** . . . . . . -0.021* . . . . . . . . . . . 3 1 0.73

Total 4 6 6 13 16 17 11 7 4 5 7 9 4 5 5 6 8 7 7 9 5 10 14 6
110

Table 5-8. Results of the regression of the hay (excluding alfalfa) yield on precipitation and temperature

prior to- and during the growing season

Prod_Pract Irrigated State Constant Trend P_prior P_during T_prior T_during Rsq

All No AL 4.319** 0.020*** 0 0.001*** -0.08 -0.088 0.68

All No AZ 2.733 -0.014 -0.002** 0.003 -0.052 0.082 0.33

All No IL 2.181 0.003 -0.001* 0.001 -0.036 0.011 0.32

All No KS 3.364*** -0.005* 0 0.001*** -0.014 -0.099** 0.61

All No KY 1.66 0.007* 0 0.001*** 0.032 -0.035 0.53

All No MN 1.690* -0.015*** 0 0.001* -0.003 -0.001 0.38

All No NE 0.439 0.008*** 0 0.001*** -0.003 0.006 0.76

All No NV -1.92 0.053*** 0.002 0.001 0.034 0.147 0.65

All No NJ 6.137*** -0.011** 0 0 0.05 -0.231*** 0.55

All No NM 1.786 0.024 0.002 0 0.188 -0.068 0.19

All No NY 2.186*** -0.009*** 0 0.001* 0.002 -0.032 0.37

All No ND 0.307 0.010*** 0.001** 0.002*** -0.008 0 0.67

All No OK 3.011*** 0 0.001*** 0.001*** -0.024 -0.088** 0.61

All No OR 1.658* 0.005 0 0.001 -0.002 0.01 0.12

All No PA 2.219* 0.006 0 0.001** 0.008 -0.048 0.29

All No SD 1.563 -0.002 0 0.002*** 0.008 -0.064 0.56

All No TN 2.512** 0.002 0 0.001*** 0.023 -0.051 0.42

All No UT 2.612** 0.007 0 0.001 0.013 -0.06 0.34

All No VA 4.656** 0.015* 0 0.001** 0.018 -0.176* 0.5

All No WA 3.735** 0.003 0 0 -0.008 -0.083 0.04

All No WV 3.560*** 0.010** 0 0.001 0.01 -0.132* 0.31

All No WI 1.605 -0.020*** 0.001 0.002*** -0.011 -0.031 0.45

All Yes AZ 9.491 0.027 -0.001 -0.001 -0.063 -0.236 0.12

All Yes CO 1.469 0.004 0.001 0.001 -0.014 -0.036 0.26

All Yes KS 0.571 -0.001 -0.001 0.002 0.097 0.036 0.12

All Yes MT 0.848 0.007*** 0 0.002*** 0.013 -0.001 0.54

All Yes NE 0.266 0.014*** 0 0.001 -0.043 0.047 0.36

All Yes NV 1.509 0.024*** 0.001 0.001 0.035 -0.035 0.68

All Yes NM 0.642 0.008 0.001 0 -0.091 0.076 0.21

All Yes OR 1.777 0.021*** 0 0.001 0.02 -0.046 0.55

All Yes UT 3.232*** 0.011** 0 0.001 -0.007 -0.076 0.48

All Yes WA 5.639 0.082*** -0.001 0.004* -0.107 -0.205 0.54

All Yes WY 0.368 0.008*** 0 0.003*** 0.009 0.012 0.66

Irrig Yes CO -0.329 0.014*** 0.003*** 0.002** -0.060** 0.052 0.7

Irrig Yes MT 1.016 0.018*** 0 0.002* -0.011 0.005 0.54

Irrig Yes WY 0.788 0.012*** 0.001 0.002 -0.011 -0.006 0.48

Non_Irrig Yes CO -0.462 0.002 0.001 0.002 -0.066 0.056 0.11

Non_Irrig Yes MT 0.111 0.009** 0 0.003*** 0.018 0.005 0.46

Non_Irrig Yes WY -0.607 -0.001 0 0.004*** -0.03 0.034 0.67
111

Table 5-9. Results of the stepwise regression of the hay (excluding alfalfa) yield on current and eleven lagged values of PDSI using county-level data

Prod_Pract Irrigated State Constant Trend PDSI1 PDSI2 PDSI3 PDSI4 PDSI5 PDSI6 PDSI7 PDSI8 PDSI9 PDSI10 PDSI11 PDSI12 PDSI_max Rsq

All No AL 1.891*** 0.018*** . . . . . . . 0.091*** . . . . 1 0.72

All No AZ 3.981*** . . . . . . . . . . . . . 0 0

All No IL 2.272*** . . . . . . 0.056** . . . . . . 1 0.18

All No KS 1.843*** -0.006** -0.044** . . . . . . . 0.089*** . . . 2 0.53

All No KY 1.945*** 0.007** . . . . . . . . 0.070*** . -0.027* . 2 0.52

All No MN 2.180*** -0.017*** . . . . . . 0.067*** . . . . . 1 0.53

All No NE 1.096*** 0.010*** . -0.068*** . . 0.050** 0.043** . . . . . . 3 0.74

All No NV 1.005*** 0.055*** . . . . . . . . . . . . 0 0.62

All No NJ 2.204*** -0.020*** . . . . -0.181*** 0.131*** . . 0.042* . -0.139* 0.178** 5 0.74

All No NM 1.767*** 0.026** . . . . . . . . . . . . 0 0.15

All No NY 2.018*** -0.008*** . . . . . . . . . . . . 0 0.26

All No ND 1.319*** 0.004* -0.042** . . . . 0.140*** . . . . . . 2 0.79

All No OK 1.593*** . . . . . . . . 0.077*** . -0.034** . . 2 0.47

All No OR 2.137*** . . . . . . . . . . . . . 0 0

All No PA 2.061*** . . . . . . . . . 0.076*** . . . 1 0.31

All No SD 1.423*** . . . -0.065** . . . 0.120*** . . . . . 2 0.72

All No TN 2.098*** . -0.071*** . . . . . . 0.078*** . 0.183** -0.141* . 4 0.54

All No UT 1.789*** 0.007** . . . . . . . 0.034*** . . . . 1 0.42

All No VA 2.108*** . . . -0.133*** 0.082 . . . 0.126*** . . . . 3 0.76

All No WA 2.598*** . . . . . . . . . . . . . 0 0

All No WV 1.605*** 0.009** . . . . . . . . . . . . 0 0.14

All No WI 2.318*** -0.022*** . . . . . . . 0.111*** . . . . 1 0.49

All Yes AZ 3.865*** . . . . . . . . . . . . . 0 0

All Yes CO 1.604*** . . . . . . . . . 0.038** . . . 1 0.14

All Yes KS 2.374*** . . . . . . . . . . . . . 0 0

All Yes MT 1.338*** 0.007*** . . . . -0.074*** . 0.109*** . . . . . 2 0.67

All Yes NE 1.375*** 0.013*** -0.086* . . . 0.107** . . . . . . . 2 0.4

All Yes NV 1.168*** 0.026*** . . . . . . . . 0.035*** . . . 1 0.7

All Yes NM 1.868*** . . . . . . . . . . -0.042** . . 1 0.13

All Yes OR 1.607*** 0.022*** . . . -0.100** 0.136*** . . . . . . . 2 0.62

All Yes UT 2.113*** 0.011*** . . . . -0.129*** . . 0.135*** . . . . 2 0.55

All Yes WA 2.980*** 0.069*** . . . . . . . . . . . . 0 0.41

All Yes WY 1.175*** 0.010*** -0.029* . . . . . 0.073*** . . . . . 2 0.7

Irrig Yes CO 1.540*** 0.021*** . . . . . -0.100** 0.146*** . . . . 0.041*** 3 0.82

Irrig Yes MT 1.649*** 0.016*** . . . . -0.086*** . 0.149*** . -0.048* . . . 3 0.69

Irrig Yes WY 1.261*** 0.013*** -0.036** . . . . . . . 0.066*** . . . 2 0.55

Non_Irrig Yes CO 1.227*** . . . . . . . . . . . . . 0 0

Non_Irrig Yes MT 0.950*** 0.009** . . . . -0.083** . 0.129*** . . . . . 2 0.55

Non_Irrig Yes WY 0.860*** . . . . . . . . 0.102*** . . . -0.051*** 2 0.73

Total 6 1 2 2 8 5 7 7 8 3 3 3
112

Table 5-10. Results of the regression of the hay (excluding alfalfa) yield on PDSI before- and during the 

growing season using county-level data

Prod_Pract Irrigated State Constant Trend PDSI_prior PDSI_during Rsq

All No AL 1.878*** 0.020*** -0.063** 0.143*** 0.73

All No AZ 4.303*** -0.022 -0.04 -0.036 0.08

All No IL 2.280*** -0.001 -0.014 0.071 0.16

All No KS 1.818*** -0.005** -0.068*** 0.108*** 0.42

All No KY 1.906*** 0.010*** -0.039 0.073*** 0.43

All No MN 2.184*** -0.017*** -0.021 0.088*** 0.51

All No NE 1.110*** 0.009*** -0.035** 0.065*** 0.69

All No NV 0.929*** 0.060*** 0.092 -0.048 0.65

All No NJ 2.135*** -0.016*** -0.008 0.028 0.33

All No NM 1.733*** 0.028** -0.11 0.12 0.18

All No NY 2.022*** -0.009*** -0.024 0.024 0.31

All No ND 1.316*** 0.005* -0.047** 0.142*** 0.76

All No OK 1.600*** 0 -0.050** 0.095*** 0.42

All No OR 2.057*** 0.005* -0.022 0.031* 0.14

All No PA 1.925*** 0.007* -0.037 0.094*** 0.32

All No SD 1.422*** 0 -0.072** 0.142*** 0.67

All No TN 2.055*** 0.005 -0.025 0.065*** 0.34

All No UT 1.798*** 0.007* -0.023 0.056* 0.39

All No VA 2.015*** 0.006 -0.096*** 0.165*** 0.67

All No WA 2.545*** 0.003 -0.02 0.014 0.01

All No WV 1.634*** 0.007* -0.028 0.044 0.18

All No WI 2.320*** -0.022*** 0.013 0.104** 0.44

All Yes AZ 3.132*** 0.049** 0.227* -0.082 0.22

All Yes CO 1.510*** 0.005 -0.009 0.051* 0.16

All Yes KS 2.293*** 0.005 -0.004 0.041 0.04

All Yes MT 1.342*** 0.007*** -0.033** 0.064*** 0.53

All Yes NE 1.378*** 0.013*** -0.009 0.032 0.31

All Yes NV 1.173*** 0.026*** 0.008 0.031 0.69

All Yes NM 1.758*** 0.006 -0.038 0.023 0.13

All Yes OR 1.625*** 0.021*** -0.025 0.057** 0.57

All Yes UT 2.143*** 0.009** -0.070* 0.089** 0.44

All Yes WA 2.926*** 0.073*** -0.312** 0.281** 0.52

All Yes WY 1.188*** 0.009*** -0.026 0.076*** 0.68

Irrig Yes CO 1.535*** 0.021*** 0.026 0.060** 0.69

Irrig Yes MT 1.633*** 0.018*** -0.031 0.057** 0.51

Irrig Yes WY 1.303*** 0.010*** -0.043** 0.070*** 0.49

Non_Irrig Yes CO 1.109*** 0.008 -0.028 0.072 0.07

Non_Irrig Yes MT 0.956*** 0.009** -0.042 0.086*** 0.37

Non_Irrig Yes WY 0.885*** -0.002 -0.068*** 0.120*** 0.68
113

Table 5-11. Results of the nonlinear regression of the hay (excluding alfalfa) yield on precipitation and temperature and neighboring states

Prod_Pract Irrigated State Constant Trend P_prior P_during T_prior T_during P_prior^2 P_during^2 T_prior^2 T_during^2 NB_P NB_T Rsq

All No AL -95.47* 0.017*** 0.005 0.004* -2.515** 9.391** 0 0 0.108** -0.203** -0.001 0.007 0.82

All No AZ -191.8** -0.025* -0.004 -0.023 0.174 17.520** 0 0.000* -0.01 -0.395** 0.014** 0.261***0.71

All No IL 19.015 0.006 0.012 0.003 0.015 -2.054 0 0 -0.008 0.053 -0.002 -0.003 0.43

All No KS 18.348 -0.005* -0.002 0.004 0.041 -1.632 0 0 -0.005 0.037 0.001 -0.004 0.66

All No KY -16.62 0.010** -0.002 0.005* 0.365 1.568 0 0 -0.027 -0.038 -0.002* -0.002 0.62

All No MN -16.37 -0.016*** -0.001 -0.003 -0.019 2.493 0 0 -0.002 -0.082 0.002 0.029 0.49

All No NE 8.025 0.010*** -0.002 0.005* 0.015 -0.938 0 0 -0.009 0.027 0.001 0.017 0.81

All No NV 4.28 0.062*** 0.023 0.007 0.644 -0.867 0 0 -0.113 0.028 0.011* -0.033 0.8

All No NJ 60.805* -0.011** -0.004* 0.001 0.984** -6.310* 0.000* 0 -0.107** 0.166* -0.001 -0.038* 0.79

All No NM -134.5 0.036 -0.007 -0.024 -3.812* 16.561 0 0 0.329* -0.451 0.005 -0.092 0.35

All No NY -6.791 -0.007** -0.003 0.002 -0.008 1.1 0 0 -0.013 -0.035 -0.002***0.02 0.61

All No ND -3.397 0.006** 0.004*** 0.005 0.136** 0.4 -0.000** 0 0.013* -0.013 0.003** 0.006 0.8

All No OK -21.15 -0.003 0.002 0.003** -0.35 1.904 0 0 0.021 -0.042 0.002** 0.089***0.81

All No OR -12.75 0.002 0.001 -0.009 0.18 2.101 0 0.000* -0.029 -0.073 0.002 0.007 0.29

All No PA -11.08 0.003 0.012* 0.003 0.045 1.045 -0.000* 0 -0.012 -0.032 0.001 0.015 0.46

All No SD 16.001 0 -0.01 0.017* 0.025 -2.119 0 0 0.01 0.062 0.001 0.044 0.77

All No TN -41.82** 0.004 0.004 0.009*** 0.615* 3.501* 0.000* -0.000*** -0.039* -0.084* -0.001 0.032 0.75

All No UT 17.706 0.005 0.003 0.002 0.046 -1.974 0 0 -0.012 0.057 0.003 0.031 0.46

All No VA -58.66 0.015 0.003 -0.002 -0.03 6.141 0 0 0.002 -0.155 -0.002 -0.011 0.61

All No WA 6.107 0.003 0.001 0.004 0.427 -0.517 0 0 -0.068 0.015 -0.001 -0.08 0.24

All No WV -16.77 0.013** -0.002 0.005 0.596* 1.829 0 0 -0.071* -0.053 -0.002 0.017 0.48

All No WI -9.488 -0.021*** 0.004 0.01 0.066 0.933 0 0 0.016 -0.03 0 0.087** 0.64

All Yes AZ -69.46 0.023 -0.006 -0.022 0.96 6.642 0 0 -0.062 -0.158 0.014 0.19 0.22

All Yes CO -11.31 0.003 0.027* -0.007 0.002 1.596 -0.000* 0 -0.005 -0.055 0.001 -0.049 0.4

All Yes KS -19.23 0 0 -0.011 0.699 1.984 0 0 -0.066 -0.047 0.004 0.089 0.27

All Yes MT 1.51 0.006** 0.003 0.002 0.002 -0.163 0 0 -0.006 0.006 0.001 0.019 0.58

All Yes NE 21.658 0.016*** -0.008 0.006 0.001 -2.503 0 0 -0.023 0.071 0.001 0.067 0.49

All Yes NV -8.207 0.026*** 0 0.002 0.032 1.258 0 0 0 -0.04 0 -0.059* 0.79

All Yes NM 25.983 0.007 0.006 -0.003 0.572 -2.883 0 0 -0.056 0.081 -0.002 -0.022 0.35

All Yes OR -27.53 0.020*** 0.003 -0.004 0.108 4.137 0 0 -0.008 -0.15 0.002 -0.027 0.68

All Yes UT -7.659 0.013*** -0.004 0.002 -0.035 1.194 0 0 -0.001 -0.039 0.007** 0.074** 0.76

All Yes WA -51.12 0.084*** 0.009* 0.019 1.229** 6.858 -0.000* 0 -0.228* -0.252 -0.004 -0.086 0.76

All Yes WY -0.904 0.006*** 0.014*** 0.002 0.154*** -0.035 -0.000*** 0 0.040*** 0.003 0 0.043***0.84

Irrig Yes CO -18.67 0.018*** 0.028* -0.005 -0.102* 2.528 -0.000* 0 0.011 -0.086 0.001 -0.071 0.8

Irrig Yes MT -5.05 0.018*** -0.006 -0.002 -0.115 1.058 0 0 -0.031 -0.039 0 0.006 0.59

Irrig Yes WY 3.59 0.009** 0.01 0.007 0.054 -0.744 0 0 0.02 0.029 0.002 0.059* 0.65

Non_Irrig Yes CO 14.575 0.014 0.036 -0.004 -0.281 -2.284 0 0 0.063* 0.078 -0.002 0.032 0.33

Non_Irrig Yes MT -13.74 0.007 0.002 -0.003 -0.012 2.088 0 0 -0.014 -0.076 0.002 0.02 0.55

Non_Irrig Yes WY 9.693 -0.004 0.014* 0.008 0.036 -1.877 -0.000* 0 0.014 0.076 -0.002 0.013 0.8
114

Table 5-12. Results of the nonlinear regression of the hay (excluding alfalfa) yield on PDSI and 

neighboring states using county-level data

Prod_Pract Irrigated State Constant Trend PDSI_prior PDSI_during PDSI_prior^2 PDSI_during^2 NB_PDSI Rsq

All No AL 1.893*** 0.000*** -0.067** 0.117*** 0.01 -0.006 0.033 0.76

All No AZ 4.268*** 0.164*** -0.026 -0.034 0.022 -0.007 -0.057 0.15

All No IL 2.309*** 0.944*** -0.013 0.072 0.012 -0.026 0.018 0.22

All No KS 1.738*** 0.072*** -0.062*** 0.060** 0.013** -0.003 0.068*** 0.63

All No KY 1.945*** 0.086*** -0.044* 0.033 0.019* -0.011 0.089* 0.55

All No MN 2.167*** 0.000*** -0.03 0.079** 0.024** -0.015 0.025 0.59

All No NE 1.100*** 0.000*** -0.023 0.045* 0.004 -0.003 0.016 0.7

All No NV 0.762*** 0.000*** 0.044 -0.187*** -0.005 0.005 0.214*** 0.79

All No NJ 2.239*** 0.004*** 0.01 -0.019 0.025 -0.021 0.052* 0.44

All No NM 1.955*** 0.085*** -0.113 0.168 0.013 -0.054* -0.091 0.29

All No NY 2.037*** 0.003*** -0.025 0.043* -0.004 0.003 -0.026 0.35

All No ND 1.380*** 0.037*** -0.062*** 0.172*** -0.001 -0.013** -0.03 0.81

All No OK 1.648*** 0.847*** -0.080*** 0.117*** 0.018*** -0.031*** 0.025 0.7

All No OR 2.042*** 0.032*** -0.019 -0.02 0.015* -0.013 0.065** 0.38

All No PA 2.016*** 0.355*** -0.041 0.045 -0.005 -0.019 0.046 0.43

All No SD 1.417*** 0.554*** -0.025 0.124*** 0.022* -0.026* -0.035 0.74

All No TN 2.032*** 0.266*** -0.03 0.065** 0.014* -0.011 0.018 0.46

All No UT 1.837*** 0.086*** -0.009 0.024 -0.002 -0.01 0.02 0.5

All No VA 1.951*** 0.073*** -0.132*** 0.225*** 0 0.009 -0.054 0.75

All No WA 2.449*** 0.457*** -0.013 -0.002 0.009 0.005 0.024 0.06

All No WV 1.601*** 0.214*** -0.037 0.04 0.034*** -0.018 0.029 0.44

All No WI 2.318*** 0.000*** 0.015 0.077 0.005 -0.021 0.035 0.51

All Yes AZ 2.944*** 0.059*** 0.197 -0.062 -0.003 0.047 -0.003 0.31

All Yes CO 1.582*** 0.280*** -0.014 0.027 0.001 -0.009 0.045 0.25

All Yes KS 2.260*** 0.416*** 0 0.001 -0.008 0.006 0.064 0.06

All Yes MT 1.346*** 0.000*** -0.032* 0.058*** 0.004 -0.005 0.01 0.55

All Yes NE 1.372*** 0.007*** 0.021 -0.001 0.019* -0.017 0.009 0.39

All Yes NV 1.145*** 0.000*** -0.01 -0.007 -0.002 -0.003 0.067** 0.77

All Yes NM 1.772*** 0.385*** -0.039 0.046 0.005 -0.002 -0.056 0.19

All Yes OR 1.606*** 0.000*** -0.029 -0.007 0.012 -0.011 0.096*** 0.7

All Yes UT 2.089*** 0.009*** -0.037 0.055 0.015* -0.008 0.018 0.57

All Yes WA 2.913*** 0.000*** -0.297** 0.263* 0.034 -0.032 0.001 0.54

All Yes WY 1.237*** 0.000*** -0.026 0.082*** 0 -0.008 -0.013 0.72

Irrig Yes CO 1.527*** 0.000*** 0.027 0.067** 0.004 -0.002 -0.011 0.7

Irrig Yes MT 1.619*** 0.001*** -0.038 0.069* 0.001 0.01 0 0.55

Irrig Yes WY 1.318*** 0.001*** -0.058** 0.068*** 0.012 -0.015** 0.033 0.63

Non_Irrig Yes CO 1.168*** 0.476*** -0.023 0.083 -0.011 -0.01 -0.04 0.15

Non_Irrig Yes MT 0.961*** 0.050*** -0.035 0.068 0.004 -0.006 0.013 0.39

Non_Irrig Yes WY 0.918*** 0.874*** -0.054** 0.127*** -0.009 -0.003 -0.024 0.73
115

Table 5-13. Results of the stepwise regression of the alfalfa hay yield on monthly precipitation and temperature

Prod_Pract State Constant Trend P1 P2 P3 P4 P5 P6 P7 P8 P9 P10 P11 P12 T1 T2 T3 T4 T5 T6 T7 T8 T9 T10 T11 T12 P_max T_max Rsq

All AZ 7.196*** 0.035*** 0.017** 1 0 0.71

All CA 8.743*** 0.009** -0.037*** -0.005*** -0.036 0.096*** -0.098*** -0.063** 2 4 0.72

All CO 4.004*** 0.013*** 0.009*** 0.004* -0.004* 0.005*** 0.053** 0.067** -0.089** -0.056** 4 4 0.72

All ID 3.922*** 0.014*** 0.003*** -0.029* 1 1 0.65

All IL 4.575*** 0.004*** 0.004*** 0.044 -0.091*** 2 2 0.47

All IA 5.633*** -0.092** 0 1 0.13

All KS 1.587** 0.005*** 0.006*** 0.106** 2 1 0.38

All KY 1.033 -0.030*** 0.006*** 0.005*** 0.007*** 0.002* 0.063*** 0.208*** -0.183***-0.028* 4 4 0.73

All MI 3.098*** -0.029*** 0.006** 0.006** 0.004* -0.006** 4 0 0.56

All MN 2.761*** 0.006*** 0.005*** 0.032** 2 1 0.43

All MO 5.964*** 0.002** 0.003** 0.027** 0.064*** -0.065** -0.120*** 2 4 0.63

All MT 2.289*** -0.009*** 0.004** 0.001* 0.002** -0.041*** 0.032** 3 2 0.65

All NE 3.597*** 0.012*** 0.003*** 0.003*** 0.002** 0.003** -0.053*** 4 1 0.85

All NV 5.401*** 0.021*** 0.005** 0.006** -0.009*** -0.053*** -0.086*** 0.037* 3 3 0.7

All NM 6.306*** -0.006** -0.003** -0.081*** 2 1 0.35

All NY 3.152*** -0.006* -0.003** -0.070*** 1 1 0.39

All ND 0.22 0.016*** 0.006*** 0.004*** 0.004*** 0.004*** -0.022* 5 1 0.72

All OH 6.607*** -0.012** -0.004** -0.116*** 1 1 0.4

All OK 12.809*** 0.004** 0.003* 0.002* 0.003* -0.152***-0.241*** 4 2 0.73

All OR 1.801*** 0.006*** 0.001** 0.004*** 0.002* 0.001* 0.001*** 0.058*** 0.062*** 5 2 0.75

All PA 4.589*** -0.002*** -0.002** 0.002*** 0.003*** -0.001*** -0.001 -0.031*** -0.023* . -0.084*** 0.038** 6 4 0.77

All SD 1.701*** 0.016*** 0.007*** 0.004*** 0.003* 0.003*** 0.014*** -0.068*** 6 1 0.84

All TX 4.005*** 0.014** 0.007** 1 0 0.23

All UT 4.181*** 0.005*** 0.035* -0.052*** 1 2 0.47

All WI 1.622*** 0.006*** 0.003* 0.005* 3 0 0.27

Irrig CO 1.152 0.011*** 0.007** 0.007*** 0.010*** 0.193*** -0.097*** 0.059* -0.095***4 4 0.87

Irrig ID 2.994*** 0.009* 0.004*** 0.004** -0.004** 0.010*** 0.026* 0.110*** 4 2 0.86

Irrig MT 2.588*** 0.013*** 0.004** 0.008*** -0.052*** 0.076*** 2 2 0.82

Irrig NE 4.178*** 0.021*** 0 0 0.51

Non_Irrig CO 4.918*** -0.005** 0.007*** -0.187*** 2 1 0.77

Non_Irrig ID 4.529*** 0.005*** 0.001** -0.004*** 0.008*** -0.002*** -0.013* -0.036*** -0.228*** -0.020** 5 4 0.99

Non_Irrig MT 1.292*** 0.005** 0.013*** 0.004** 0.010*** 0.054*** -0.058*** -0.076*** 0.050*** 4 4 0.91

Non_Irrig NE 3.673*** 0.003*** 0.003** 0.005*** 0.037 -0.082*** -0.036*** 3 3 0.8

Total 10 4 5 8 11 10 9 3 9 17 3 4 1 9 2 4 5 8 10 4 8 6 3 3
116

Table 5-14. Results of the regression of the alfalfa hay yield on precipitation and temperature prior toand during the growing season

Prod_Pract State Constant Trend P_prior P_during T_prior T_during Rsq

All AZ 9.497*** 0.032*** -0.001 -0.002 0.074 -0.113 0.7

All CA 5.574** 0.006 0 0 -0.164* 0.135 0.15

All CO 1.442 0.008 0.003* 0.001 0.072 0.061 0.26

All ID 4.078*** 0.014*** 0.001 0 0.036 -0.047 0.58

All IL 4.004** -0.006 0 0.001** 0.018 -0.051 0.19

All IA 4.817** 0.003 0 0 0.048 -0.08 0.05

All KS 1.835 -0.006 0.001 0.002** 0.056 0.021 0.26

All KY 2.149 -0.019* 0 0.002*** -0.005 -0.003 0.27

All MI 5.289*** -0.024*** -0.002 0.003** 0.025 -0.148 0.45

All MN 2.973** -0.006 0.001 0.002*** 0.025 -0.044 0.24

All MO 4.743*** 0 0 0.001* 0.018 -0.115 0.22

All MT 1.419* -0.010*** 0.001 0.002*** 0.027 0.011 0.43

All NE 2.731*** 0.013*** 0.001* 0.002*** 0 -0.033 0.76

All NV 3.223** 0.015*** 0.001 -0.001 0.007 0.043 0.37

All NM 5.364*** 0.001 -0.001 0 -0.072* 0.017 0.15

All NY 3.591*** -0.005 0 0 -0.067** -0.056 0.28

All ND 0.044 -0.005 0.003*** 0.004*** -0.012 0.007 0.57

All OH 6.881*** -0.009 -0.001 0 -0.019 -0.164* 0.39

All OK 10.012*** -0.012** 0.002*** 0.002*** -0.008 -0.350*** 0.74

All OR 1.641** 0.010*** 0.001*** 0.002*** 0.03 0.111** 0.61

All PA 5.269*** 0 0 0 -0.029 -0.150** 0.28

All SD 1.35 -0.005 0.003** 0.004*** 0.031 -0.06 0.7

All TX 10.457** 0.027** 0.001 -0.002 0.018 -0.255 0.23

All UT 4.405*** 0.007** 0.001 0.001 0.016 -0.054 0.38

All WI 1.069 -0.004 0.001 0.003*** -0.002 -0.003 0.31

Irrig CO -2.073 -0.003 0.006** 0.003*? -0.045 0.269* 0.36

Irrig ID 3.976*** 0.021** 0.001 0.001 0.001 0.002 0.44

Irrig MT 0.868 0.015*** 0.003** 0.003** 0.043 0.071 0.54

Irrig NE 3.329*** 0.020*** 0.001 0 0.011 0.035 0.54

Non_Irrig CO 0.527 -0.014 0.004* 0.002 -0.056 -0.025 0.63

Non_Irrig ID 1.531 0 0.001* 0.002** -0.081 -0.069 0.69

Non_Irrig MT -0.273 -0.006 0.004*** 0.003** 0.044 0.005 0.54

Non_Irrig NE 3.450** -0.001 0.002* 0.002** 0.032 -0.096 0.61
117

Table 5-15. Results of the stepwise regression of the alfalfa hay yield on monthly PDSI

Prod_Pract State Constant Trend PDSI1 PDSI2 PDSI3 PDSI4 PDSI5 PDSI6 PDSI7 PDSI8 PDSI9 PDSI10 PDSI11 PDSI12 PDSI_max Rsq

All AZ 7.492*** 0.023*** -0.068** 1 0.73

All CA 6.795*** 0 0

All CO 3.231*** 0.015*** 0.066*** 1 0.28

All ID 3.808*** 0.012*** 0.057 0.050* 0.060* -0.132*** 4 0.69

All IL 3.761*** -0.101*** 0.132*** 2 0.31

All IA 3.612*** 0 0

All KS 3.814*** 0.120*** 1 0.32

All KY 3.631*** -0.019*** -0.109*** 0.198*** 2 0.42

All MI 3.764*** -0.023*** 0 0.27

All MN 3.374*** -0.008*? 0.119*** 1 0.36

All MO 2.830*** 0 0

All MT 2.321*** -0.007*** 0.099*** -0.044* -0.042** 3 0.45

All NE 3.305*** 0.012*** -0.218*** 0.144*** 0.128** 3 0.79

All NV 4.002*** 0.017*** 0 0.35

All NM 5.092*** -0.028** 1 0.12

All NY 2.564*** -0.038** 1 0.17

All ND 1.923*** -0.010** -0.220*** 0.172** 0.197*** 3 0.75

All OH 3.690*** -0.014** 0 0.17

All OK 3.606*** -0.018*** -0.136** 0.271*** 2 0.62

All OR 4.111*** 0.011*** 0.033** 1 0.41

All PA 2.898*** -0.063** 0.172*** -0.069* -0.105** 0.074 5 0.53

All SD 2.113*** -0.091*** 0.199*** 2 0.74

All TX 4.287*** 0.015** 0 0.12

All UT 3.900*** 0.009*** 0.202* 0.077*** 0.163** -0.409*** 4 0.54

All WI 2.779*** 0.118*** 1 0.25

Irrig CO 3.867*** 0.094*** 1 0.34

Irrig ID 4.474*** 0.021*** 0.048*** 1 0.54

Irrig MT 2.888*** 0.020*** 0.050** 1 0.48

Irrig NE 4.178*** 0.021*** 0 0.51

Non_Irrig CO 1.235*** 0.109*** 1 0.58

Non_Irrig ID 1.653*** 0.088*** 1 0.53

Non_Irrig MT 1.231*** 0.121*** -0.043* 2 0.6

Non_Irrig NE 3.049*** -0.138** 0.095* 0.116*** 3 0.61

Total 4 1 3 4 4 0 10 5 5 5 4 2
118

Table 5-16. Results of the regression of the alfalfa hay yield on PDSI prior to- and during the growing 

season 

Prod_Pract State Constant Trend PDSI_prior PDSI_during Rsq

All AZ 7.481*** 0.024*** -0.076* 0.01 0.72

All CA 6.666*** 0.007 0.041 -0.017 0.06

All CO 3.242*** 0.015*** 0.006 0.062 0.26

All ID 3.737*** 0.015*** -0.003 0.034* 0.56

All IL 3.860*** -0.005 -0.108** 0.141** 0.19

All IA 3.517*** 0.005 -0.051 0.031 0.04

All KS 3.809*** -0.001 -0.046 0.155** 0.27

All KY 3.465*** -0.009 -0.091* 0.137** 0.18

All MI 3.863*** -0.028*** -0.096 0.133* 0.34

All MN 3.365*** -0.008 -0.014 0.135** 0.32

All MO 2.844*** 0 -0.098** 0.097** 0.18

All MT 2.311*** -0.007*** -0.044** 0.067*** 0.33

All NE 3.283*** 0.013*** -0.105*** 0.169*** 0.73

All NV 3.993*** 0.017*** -0.003 0.014 0.35

All NM 5.160*** -0.003 -0.03 -0.009 0.13

All NY 2.702*** -0.007* -0.028 0.016 0.15

All ND 1.938*** -0.010** -0.102*** 0.254*** 0.67

All OH 3.646*** -0.013* -0.076 0.058 0.22

All OK 3.484*** -0.012* -0.108** 0.234*** 0.54

All OR 4.098*** 0.012*** 0.015 0.021 0.41

All PA 3.007*** -0.004 -0.050* 0.089*** 0.26

All SD 2.175*** -0.003 -0.093** 0.223*** 0.68

All TX 4.288*** 0.015** -0.033 0.055 0.14

All UT 3.924*** 0.008** -0.057 0.095*** 0.36

All WI 2.892*** -0.006 -0.001 0.159** 0.26

Irrig CO 3.680*** 0.014 0.049 0.066 0.36

Irrig ID 4.468*** 0.021*** 0.021 0.029 0.52

Irrig MT 2.886*** 0.020*** -0.01 0.054 0.43

Irrig NE 4.185*** 0.021*** -0.036 0.033 0.54

Non_Irrig CO 1.377*** -0.011 -0.025 0.119*** 0.58

Non_Irrig ID 1.734*** -0.008 -0.042 0.120*** 0.52

Non_Irrig MT 1.239*** 0 -0.048 0.131*** 0.49

Non_Irrig NE 3.060*** -0.001 -0.120*** 0.200*** 0.56
119

Table 5-17. Results of the nonlinear regression of the alfalfa hay yield on precipitation and temperature and neighboring states

Prod_Pract State Constant Trend P_prior P_during T_prior T_during P_prior^2 P_during^2 T_prior^2 T_during^2 NB_P NB_T Rsq

All AZ -32.92 0.037*** 0.003 0.003 1.36 2.874 0 0 -0.065 -0.065 0.004 0.099** 0.8

All CA 25.953 0.003 0.002 -0.001 2.671*** -3.281 0 0 -0.142*** 0.085 0.001 -0.053 0.58

All CO -17.48 0.008 0.060*** -0.009 -0.018 2.232 -0.000*** 0 0.033 -0.075 0.003 -0.038 0.47

All ID -7.895 0.017*** -0.001 -0.009 0.002 2.020* 0 0 -0.018 -0.079* -0.001 -0.003 0.69

All IL 12.43 -0.002 -0.005 0.012*** 0.26 -1.212 0 -0.000** -0.043* 0.031 0.001 0.015 0.49

All IA -13.36 0.001 0.002 0.017*** 0.025 1.196 0 -0.000*** 0.008 -0.033 0 0.036 0.69

All KS 29.118 -0.012 -0.004 0.018** -1.037* -2.851 0 -0.000** 0.126* 0.07 0.005 0.048 0.43

All KY -85.14 -0.019* 0.001 0.008 0.01 8.281 0 0 -0.001 -0.2 -0.002 -0.005 0.35

All MI -5.146 -0.022*** 0.017 0.022 0.036 0.1 0 0 0.004 -0.007 -0.003 0.054 0.53

All MN -11.26 -0.009 -0.004 0.015 0.105 1.412 0 0 0.009 -0.047 -0.001 0.034 0.35

All MO -31.21 0.001 0.002 0.009** 0.195 3.006 0 -0.000* -0.017 -0.075 0 -0.003 0.43

All MT -1.552 -0.011*** -0.008 0 -0.037 0.604 0 0 -0.023 -0.022 0.002 0.006 0.52

All NE -25.35 0.016*** 0.007 -0.001 0.077 3.159 0 0 -0.035* -0.09 -0.001 0.021 0.83

All NV -39.47* 0.012* -0.005 -0.013 -0.118 5.508* 0 0 0.022 -0.166* 0 -0.049 0.52

All NM 4.261 0.001 -0.006* 0 0.115 0.177 0 0 -0.015 -0.005 0 -0.025 0.27

All NY -51.19*** -0.002 -0.003 0.001 -0.057* 7.004*** 0 0 0.009 -0.226*** -0.003** 0.035 0.59

All ND -2.058 -0.007 0.001 0.016** 0.11 -0.024 0 -0.000* 0.012 0.001 0.002 0.05 0.69

All OH -22.37 -0.01 0.005 0.010* 0.229 2.426 0 -0.000* -0.044 -0.069 -0.002 0.042 0.56

All OK -50.64 -0.007 0.004 0.002 -0.229 4.713 0 0 0.015 -0.108 0.001 0.111** 0.83

All OR -12.54 0.015*** -0.001 0.005 -0.017 2.142 0 0 0.006 -0.074 0 0.031 0.68

All PA -14.86 -0.003 0.004 0.006** 0.005 1.782 0 0.000** -0.014 -0.055 0 0.038 0.49

All SD -8.677 -0.007 -0.001 0.012 0.059 0.925 0 0 0.011 -0.029 0.001 0.024 0.74

All TX -124.2 0.032** 0.002 -0.01 2.001 9.857 0 0 -0.08 -0.205 0.001 -0.068 0.32

All UT 12.438 0.008** 0.010** 0.009 -0.062 -1.174 -0.000* 0 0.028 0.034 -0.004 -0.039* 0.53

All WI -6.856 -0.006 -0.001 0.013 0.104 0.684 0 0 0.02 -0.023 0.002 0.04 0.49

Irrig CO -39.93 -0.007 0.027 0.004 -0.245 5.218 0 0 0.174 -0.17 0.006* -0.045 0.65

Irrig ID -5.268 0.020* 0.003 -0.001 0.041 1.582 0 0 0.019 -0.063 0.002 -0.091 0.65

Irrig MT -23.74* 0.014** -0.021 -0.008 -0.077 4.209* 0.000* 0 -0.043* -0.153* 0.003 0.01 0.71

Irrig NE 13.857 0.025*** -0.007 0.013* 0.032 -1.424 0 -0.000* -0.016 0.04 -0.001 0.048 0.75

Non_Irrig CO 21.583 -0.014 0.032 0.004 -0.068 -3.34 0 0 -0.042 0.112 0.005* 0.036 0.74

Non_Irrig ID -12.4 -0.003 0.004 -0.017 -0.045 2.259 0 0 0.062 -0.088 0.002 0.009 0.81

Non_Irrig MT -21.75* -0.008* -0.024** -0.017** -0.121* 3.922** 0.000** 0.000** -0.060*** -0.145** 0.005** 0.029 0.83

Non_Irrig NE -3.253 0.001 0.002 0.013 0.023 0.371 0 0 0.005 -0.014 0.001 0.033 0.71
120

Table 5-18. Results of the nonlinear regression of the alfalfa hay yield on PDSI and neighboring states

State Constant Trend P P(1) P(2) P(3) P(4) P(5) P(6) P(7) P(8) P(9) P(10) P(11) T T(1) T(2) T(3) T(4) T(5) T(6) T(7) T(8) T(9) T(10) T(11) P_max T_max Rsq

AZ 1.438*** 0.001*** -0.001** 0.010*** 0.006** 1 2 0.3

AR 1.076*** 0.000** 0.002** 0 1 0.05

CA 1.892*** 0.001*** -0.008*** 0 1 0.16

CO 2.021*** 0.002*** -0.001* -0.001** -0.002** -0.002***-0.002** -0.002***-0.002***-0.002***-0.002** -0.005*** 9 1 0.54

ID 1.506*** 0.001*** -0.008** -0.012*** 0 2 0.32

IL 1.459*** 0.001*** 0.004*** 0 1 0.12

IN 1.681*** 0.002*** -0.001** -0.002***-0.001** -0.001** 0.013*** 4 1 0.27

IA 2.499*** 0.001*** -0.001* -0.001** -0.001* -0.001** -0.001***-0.001* -0.011** -0.010* -0.012** -0.017*** -0.013*** -0.013*** -0.013*** 6 7 0.2

KS 2.331*** 0.001*** -0.001** -0.001* -0.001** -0.001* -0.001** -0.001***-0.001***-0.001***-0.001* -0.001* -0.001** -0.011** -0.009* -0.008* -0.012*** 11 4 0.23

KY 1.629*** -0.000** -0.000* -0.001** 2 0 0.06

MI 1.830*** 0.001*** -0.001* -0.001* -0.001* -0.001* -0.001* -0.001** -0.001*** -0.012*** 7 1 0.29

MN 2.533*** -0.000** -0.001** -0.001***-0.001* -0.001***-0.001***-0.001** -0.001** -0.001** -0.001** -0.014***-0.014*** -0.009** -0.012** -0.011** -0.008* -0.008*? -0.010** 9 8 0.26

MO 1.261*** -0.001*** 0.005** 0.008*** 0 2 0.21

MT 1.780*** 0.000** -0.001 -0.002** -0.002***-0.002***-0.002***-0.002*** -0.007*** 6 1 0.14

NE 2.302*** 0.001*** -0.001***-0.001***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002*** -0.011*** -0.009** -0.013*** 11 3 0.38

NV 1.711*** 0.001*** 0 0 0.15

NM 1.843*** 0.001*** -0.001** -0.001** -0.001** 0.010*** 0.016*** 3 2 0.26

NY 1.775*** 0.000*** -0.001* -0.001* 2 0 0.04

ND 1.015*** -0.000*** -0.005*** 0.004*** 0.010*** 0 3 0.08

OH 1.551*** -0.001*** 0.020*** 0.003 0.016*** 0 3 0.07

OK 1.745*** -0.001*** -0.001** -0.000* -0.001*** -0.001***-0.001***-0.001** -0.000* 0.010*** . 7 1 0.24

OR 1.722*** 0.002*** -0.007* -0.013*** 0 2 0.42

PA 2.061*** 0.000*** -0.001** 1 0 0.04

SD 1.044*** 0.001*** 0.002* 0 1 0.08

TX 1.423*** -0.000** -0.001* -0.001** -0.001** . -0.001** -0.001** -0.001** 0.014*** 0.009** 6 2 0.16

UT 1.376*** 0.001*** -0.003** 0 1 0.27

WA 2.633*** 0.002*** -0.022***-0.019*** -0.022***-0.022*** -0.017** -0.020*** 0 6 0.35

WI 2.038*** -0.001** -0.001*** -0.001* -0.002***-0.002***-0.001** -0.014*** 6 1 0.14

WY 1.713*** 0.001*** -0.002*** -0.001** -0.001* -0.002** -0.001* -0.002** 6 0 0.16

Total 0 2 5 7 7 9 10 13 12 11 11 10 6 6 6 3 4 4 4 8 4 4 5 3
121

Chapter 6 Targeting PRF to Viable Regions

At present, the PRF plan is offered across a geography that largely covers the entire coterminous 

United States. Not all areas where the PRF plan is offered are suitable for forage production. 

We have investigated two distinct measures of the suitability of land for the production of forage 

with the intent of formulating recommendations for restricting the PRF offering to areas that 

have the potential for viable forage and hay production. 

The National Resources Inventory (NRI) is a periodic survey that catalogs the stock of US 

natural resources, including land capability and usage. The survey includes a measure of the 

suitability of non-irrigated soils for most kinds of field crops—the land capability classification 

(LCC). The Natural Resources Conservation Service (NRCS) has constructed quantitative 

measures of land characteristics to formulate the LCC system. Soils are grouped according to 

their limitations, their response to management, and the potential for damage if the land is 

cropped. The LCC ranges from scores of 1 to 8, with 1 being of the highest quality for 

agronomic uses and 8 corresponding to the lowest quality. An LCC of 1 corresponds to soils that 

have few limitations that restrict their use. The lowest quality of land has an LCC score of 8. 

This corresponds to “soils and miscellaneous areas that have limitations that preclude 

commercial plant production and that restrict their use to recreational purposes, wildlife habitat, 

watershed, or esthetic purposes.” 

The LCC system also has a set of four subclasses that correspond to additional hazards that affect 

their use. We believe that subclass C characterizes hazards that are likely to limit the suitability 

of the land for cultivation or forage production. Subclass C consists of soils for which the 

climate (based on temperature or lack of moisture) is the major limitation affecting their use. 

We used the 2015 NRI survey (the most recent available) to consider the suitability of individual 

counties for inclusion in the PRF plan. The NRI data are not geographically identifiable at a 

resolution any finer than the county level due to non-disclosure considerations and the sampling 

procedures used in collecting the data. 

We considered various aggregations of land area in each county according to the LCC metrics. 

Figure 6-1 illustrates the proportions of land area that falls into LCC class 8 and/or subclass C 

(which we denote as LCC 8/C). This represents the land least suitable for cultivation because of 

soil and climate conditions. As would be expected, the lowest quality of land is generally in the 

western states. Some coastal regions also have land that is not designated as being useful for 

cultivation.

We investigated the extent of the usage of land area in the production of hay and forage. 

Specifically, we considered the proportion of total area in a county, as reported in the 2017 

Agricultural Census, that was harvested for forage, defined as “all hay and haylage, grass silage, 
122

and green-chop,” (Agricultural Census Variable No. y17-M159). This was converted to a 

proportion of total area in a county by using the proportions of cropland harvested and land in 

farms as a proportion of total land area. We considered three different thresholds for the 

proportion of land in LCC 8 or C—counties with more than 10%, 25%, and 50% of land so 

designated. We identified such counties and examined the proportion of land in each county that 

was harvested for forage. 

Figures 6-2 – 6-4 illustrate the proportion of land in each category of LCC rating 8/C used in 

producing forage. In each figure, the shorter bar reflects the proportion of LCC 8/U land 

exceeding each threshold in a county used in forage production. It is notable that counties 

having 10% or 25% of land area in LCC 8/C still have notable acreage devoted to the production 

of forage. In the case of those counties having more than 50% of land area in LCC 8/C, less than 

1% of land area is harvested for forage or hay. 

Figures 6-5 – 6-7 identify the counties exceeding each threshold (10%, 25%, and 50%) of land in 

LCC 8/U. We believe that the LCC measure of land quality could be used to limit the offering of 

the PRF plan in counties having a large proportion of land that is unsuitable for forage 

production. If RMA intends to limit entire counties, we would recommend eliminating those 

counties with 50% or more land area that falls into the lowest capability classes, either because 

of its suitability for cultivation or its unfavorable weather conditions. Our analysis demonstrates 

that such counties generally do not have very much land area (only about 0.95%) involved in 

forage production. This would serve to drop areas with unfavorable growing conditions and 

would have a minimal impact on forage producers that may have PRF coverage. 

An important limitation of such a proposal lies in its relative lack of resolution. That is, entire 

counties would be eliminated based on average growing conditions. To the extent that land 

quality is highly heterogeneous in such counties, this would have the potential of eliminating 

small portions of land that could be amenable to forage production. We, therefore, considered an 

alternative measure of land viability for forage production. The US Forest Service has calculated 

an annual measure (1984-2018) of rangeland productivity. Rangeland productivity, in terms of 

rangeland vegetation in pounds per acre, is calculated for the non-forest domain of the 

coterminous US using the Normalized Difference Vegetation Index (NDVI) from the Thematic 

Mapper Suite at the 250 m2

 level of resolution.11

We collected the average level of rangeland production over the 1984-2018 period. Figure 6-8 

illustrates the data at the 250 m2 level of resolution. These data were reprojected on the wgs84 

latitude and longitude coordinates and were aggregated by a factor of 40-times to allow the data 

to be managed in concert with the NOAA NCPC gridded data. The reprojected and aggregated 

data are presented in Figure 6-9. The data were then put on a latitude/longitude grid that was 

considerably finer than the NOAA NCPC precipitation data and nearest-neighbor averaging 

11 The USFS data can be downloaded from https://data.fs.usda.gov/geodata/rastergateway/rangelands/index.php. 
123

further aggregated the data to match the grid points of the NCPC grid. Neighbors were defined 

as all points within a 15 km radius of the NCPC grid centroid. 

Figure 6-10 illustrates average precipitation (from 1948-2017) and rangeland production. The 

figure demonstrates a strong relationship between precipitation and rangeland production. 

Figure 6-11 presents county-level aggregates of rangeland production. When compared to the 

LCC 8/U maps, very similar patterns of land quality and forage production are implied. We do 

not recommend using such a level of aggregation in light of the vast loss in resolution. 

We then considered benchmarks defined by the distribution of rangeland output across the entire 

non-forested US. We considered the elimination of grid points from the PRF plan that 

alternatively had rangeland production that fell below the tenth, fifth, and first percentiles. 

Figures 6-12 – 6-14 illustrate the grid points that would be eliminated from the plan under each 

threshold. If a tenth percentile was to be used as a threshold, 970 of the 13,626 grid points would 

be eliminated. If the threshold is dropped to the fifth percentile, 484 grid points would be 

eliminated. Dropping the threshold to the first percentile leads to 96 grid points be dropped from 

the program. 

PRF Viable Regions Recommendations

If RMA prefers to eliminate whole counties from the program based on the suitability of soil and 

climate conditions for forage production, we recommend consideration of the land capability 

classification. Specifically, we recommend dropping counties having more than 50% of the total 

area that falls into land capability class 8 and/or subclass C. Such land has been designated by 

NRCS to be unsuitable for cultivation. A review of the 2017 census indicates that only a very 

small proportion of land in such counties is used to harvest forage or hay. This recommendation 

comes with two caveats. First, eliminating entire counties may not be appropriate in areas where 

land quality is very heterogeneous. This reflects the lack of resolution in a county aggregate. 

Second, as is likely to be the case with any threshold criteria, the choice of 50% is admittedly 

arbitrary but is justified in light of the very limited acreage devoted to hay in forage in such 

areas. Appendix Table 2 presents the relevant FIPS codes. 

If RMA is willing to consider a higher degree of resolution and instead eliminate individual grid 

points rather than entire counties, we believe that the USFS measures of forage production 

provide an ideal metric for selecting areas to drop from coverage. We have obtained a direct 

measure of average forage production for each grid point and have also demonstrated the strong 

correspondence between precipitation and forage production. Again, one can infer that, 

depending on the threshold selected, this would impact few producers of forage and rangeland. 

This is again demonstrated by the fact that forage production is low, both in terms of output and 

acreage, in such areas. Once again, the threshold of rangeland production that defines dropping a 
124

grid point from the PRF plan is arbitrary but is directly justified by the very low level of forage 

production and concomitantly low allocation of acreage to forage in such areas. 

In summary, we recommend that RMA drop any grid point and its relevant 0.25-degree 

surrounding area that corresponds to the lowest 1-percentile of the distribution of forage 

production from eligibility for PRF coverage. This would eliminate 96 of the 13,626 grid points 

currently in the program. We have outlined alternative thresholds that could be used to eliminate 

marginal forage producing areas and believe that these may form the basis for future program 

revisions. A less drastic step would be to allow insurance in these areas, but with a reduced CBV 

and to allow irrigated acres to insure. We note that we also considered eliminating intervals with 

extremely high rates. This is an actuarial approach, but we believe that it is also a practical 

approach to the problem. 
125

Figure 6-1: Land in LCC 8 and/or Subclass C
126

Figure 6-2: Forage and Hay Production in Counties 

With LCC 8/C > 10% of Land Area
127

Figure 6-3: Forage and Hay Production in Counties 

With LCC 8/C > 25% of Land Area
128

Figure 6-4: Forage and Hay Production in Counties 

With LCC 8/C > 50% of Land Area
129

Figure 6-5: Counties with LCC 8/C > 10% of Land Area
130

Figure 6-6: Counties with LCC 8/C > 25% of Land Area
131

Figure 6-7: Counties with LCC 8/C > 50% of Land Area
132

Figure 6-8: Raw USFS Rangeland Average (1984-2018) Production
133

Figure 6-9: Aggregated and Reprojected USFS Rangeland 

Average (1984-2018) Production
134

Figure 6-10: NCPC Average Precipitation and Forage Production
135

Figure 6-11: USFS Rangeland Average (1984-2018) Production

Aggregated to County Averages
136

Figure 6- 12: Grid Points Dropped from PRF 

Based on the 10th Percentile
137

Figure 6-13: Grid Points Dropped from PRF 

Based on the 5th Percentile
138

Figure 6-14: Grid Points Dropped from PRF 

Based on the 1st Percentile

An alternative approach based on the percent of annual rainfall

One possible approach to reducing irrelevant intervals is to simply eliminate grid intervals that 

contribute a small percentage of the annual rainfall. The premise being that intervals that 

contribute a small percentage of annual rainfall have less to do with producer risk than periods of 

more significant rainfall. We evaluated this approach and the maps in Figures 6-15 – 6-26 below 

reflect the analysis of the following two conditions: 

1. if the month’s expected rainfall is less than 1/12 of the average total annual rainfall then 

the month and any associated interval is removed 

2. if the interval’s expected rainfall is less than 1/12 of the average total annual rainfall then 

the interval is removed. 
139

Two maps, one for each of the above conditions, are generated for each two-month interval. 

Grids in red are grids that would be removed if the respective condition is imposed as they fail 

the condition. Each map indicates the number of grids that would be removed. For grids in 

yellow, the month’s (interval’s) expected rainfall is greater than 1/12 but less than 1/6 of the 

average total annual rainfall. For grids in green, the month’s (interval’s) expected rainfall is 

greater than 1/6 of the average total annual rainfall. 

The first condition would result in a large number of grids being removed for almost all intervals 

and therefore is not recommended. We also examined some other variants but reached the 

conclusion this approach is highly sensitive to the specific parameters chosen. 
140

Figure 6-15 
141

Figure 6-16 
142

Figure 6-17 
143

Figure 6-19 
144

Figure 6-20 
145

Figure 6-21 
146

Figure 6-22 
147

Figure 6-23 
148

Figure 6-24 
149

Figure 6-25 
150

Figure 6-26 
151

Chapter 7 Improving the PRF loss function and weather variables

PRF is an index product that inherently has basis risk. That is the loss function is imperfectly 

correlated with actual on-farm losses when forage is reduced. Basis risk exists because

rainfall does not explain all causes of forage and hay losses. Another form of basis risk arises 

due to the grid measure not matching the rainfall at the farm. However, using the grid 

appears the smallest feasible area. So we make no recommendations in this area. 

Data for this part of the analysis consists of alfalfa hay prices ($/ton) from NASS, 

precipitation (mm), temperature (degree C), and Palmer Drought Severity Index (PDSI) 

(generally between -2 and 2) data. Data are observed monthly at the state level. 

The relationship of forage losses with replacement value

Data for this part of the analysis consists of alfalfa hay prices ($/ton) from NASS, 

precipitation (mm), temperature (degree C), and Palmer Drought Severity Index (PDSI) 

(generally between -2 and 2) data. Data are observed monthly at the state level. 

The dependent variable for this analysis consists of alfalfa hay price and other (excluding 

alfalfa) hay prices. The discussion here is for the case of other (excluding alfalfa) hay price. 

Findings are similar for the case of the alfalfa hay price. The independent variables are 

divided into two sets. The first set includes precipitation and temperature while the second 

set consists of PDSI. A trend variable is also included in both sets. Real hay prices were 

derived by deflating the nominal hay prices by the farm level implicit price deflator obtained 

from the U.S. Bureau of Economic Analysis (FRED (a), 2019). The GDP implicit price 

deflator obtained from the U.S. Bureau of Economic Analysis (FRED (b), 2019) was also 

investigated. The results were similar to the case when the farm level implicit price deflator 

was used.

Several issues were investigated:

1. What is the lag length of the monthly precipitation, temperature, and PDSI variables on 

hay prices?

2. What is the effect of the neighboring states' aggregate precipitation, temperature, and 

PDSI variables on the hay prices of a target state?

3. Is there a nonlinear (quadratic) relationship between precipitation, temperature, and PDSI 

and hay prices? 

The results for each of these issues are discussed below.
152

1. What is the lag length of the monthly precipitation, temperature, and PDSI variables on 

hay prices?

Table 7-1 presents the results of the stepwise regression of the hay price on current and 

eleven lagged values of precipitation and temperature variables. Table 7-2 presents the 

results of the stepwise regression of the hay price on current and eleven lagged values of 

PDSI variables.

Some general notation description for all the tables is provided here again. P indicates 

precipitation, T indicates temperature, and PDSI indicates the Palmer Drought Severity 

Index. The numbers in parenthesis following P, T, and PDSI indicate lags, for example, P(3) 

indicates the value of precipitation lagged by three months. The numbers without parenthesis 

following P, T, and PDSI indicate the calendar month, for example, P3 indicates the value of 

precipitation for March. X^2 indicates the square term of the variable X while NB_X 

indicates the aggregate value from the neighboring states for the variable X.

Results of Table 7-1 show that the maximum number of significant lags for precipitation 

varies from state to state from a low of zero to a high of eleven lags. For temperature, the 

number of significant lags varies from zero to eight. Additionally, all eleven lags for both 

precipitation and temperature have a significant effect on hay prices for at least one state. 

Note that current precipitation has a significant effect on hay price only for NM out of the 29 

states while current temperature has a significant effect in four states.

Results of Table 7-2 show that the maximum number of significant lags for PDSI varies from 

zero to three months. Additionally, all twelve lags have a significant effect on hay prices for 

at least one state. Results of Table 7-1 show that precipitation, temperature, and a trend 

variable explain from a low of 2% for the state of AR to a high of 65% for OR of the 

variation in hay prices. Results of Table 7-2 show PDSI explains from a low of 1% for the 

state of KS to a high of 65% for OR of the variation in hay prices. Comparing the R-squares 

from Table 7-1 and 7-2 indicates that PDSI explains the variation in hay prices better than 

precipitation and temperature in 15 of 29 states. 

2. What is the effect of the neighboring states' aggregate precipitation, temperature, and 

PDSI variables on the hay prices of a target state?

3. Is there a nonlinear (quadratic) relationship between precipitation, temperature, and PDSI 

and hay prices? 

Results of the investigation for the two remaining issues are reported in Table 7-3 for 

temperature and precipitation and Table 7-4 for PDSI, respectively. 

Results of Table 7-3 highlight several findings. First, for 16 of the 29 states that show a 

significant relationship between hay prices and precipitation exists, the relationship is 

nonlinear (quadratic). Further, the nonlinear relationship between hay prices and 
153

precipitation is of the form that hay prices are high for low levels of precipitation, prices 

decrease as precipitation increases, reaches a minimum for a certain precipitation level, and 

start rising again as precipitation level continues to increase. In other words, hay prices are 

lower within a certain optimal range of precipitation. Too little or too much precipitation 

would cause hay prices to increase. The exceptions to this form of relationship are the states 

of NV, NY, OH, and OR. This nonlinear relationship between hay prices and precipitation 

justifies the adjustment of CBVs for low levels of precipitation in such a way to allow for 

accelerated higher levels of indemnity for low levels of precipitation.

Second, a significant relationship between hay prices and temperature exists for all states, 

and for sixteen of the 29 states the relationship is nonlinear (quadratic). The direction of the 

relationship between hay prices and the temperature is not consistent across the 29 states.

Third, for 13 states in the case of precipitation and 13 states in the case of temperature, the 

aggregate precipitation and temperature of the neighboring states affect the hay prices of the 

target state.

Results of Table 7-4 show that for 22 of the 29 states a significant relationship exists between 

hay prices and PDSI, and for seventeen of these states, the relationship is nonlinear 

(quadratic). Further, similar to precipitation, for the majority of the states (ten out of 

seventeen), the nonlinear relationship between hay prices and PDSI is of the form that hay 

prices are high for low levels of PDSI, prices decrease as PDSI increases, reach a minimum 

for a certain PDSI level, and start rising again as PDSI level continues to increase. 

Assessment of the relationship between alfalfa hay prices and yields and weather 

variables

The dependent variable for this part of the analysis consists of alfalfa hay prices and alfalfa 

hay yields. Results are presented in Tables 7.5 through 7.8. Findings are similar to the 

previously discussed findings for the case of the other (excluding alfalfa) hay price and other 

(excluding alfalfa) hay yield. 

Chapter 7 References

FRED (a), 2019. https://fred.stlouisfed.org/series/A372RD3Q086SBEA. Accessed February 

2020. 

FRED (b), 2019. https://fred.stlouisfed.org/series/GDPDEF. Accessed February 2020. 
154

Table 7-1. Results of the stepwise regression of the hay (excluding alfalfa) price on current and eleven lagged values of precipitation and temperature

State Constant Trend P P(1) P(2) P(3) P(4) P(5) P(6) P(7) P(8) P(9) P(10) P(11) T T(1) T(2) T(3) T(4) T(5) T(6) T(7) T(8) T(9) T(10) T(11) P_max T_max Rsq

AZ 1.211*** 0.002*** 0.001** -0.003** 1 1 0.57

AR 1.016*** 0.002* 0 1 0.02

CA 1.495*** 0.001*** -0.000* -0.010*** 1 1 0.2

CO 2.090*** 0.002*** -0.002** -0.002***-0.002***-0.002** -0.002***-0.002***-0.003***-0.003*** -0.005** 8 1 0.45

ID 1.125*** 0.002*** -0.005* -0.007** 0 2 0.45

IL 1.177*** 0.000*** -0.000* 0.003*** 1 1 0.06

IN 1.734*** 0.001*** -0.001** -0.001***-0.001** -0.001* -0.012*** 4 1 0.24

IA 1.533*** 0.000*** -0.000* -0.000* -0.001** -0.001** -0.010*** -0.009*** -0.007** -0.006** -0.008*** 4 5 0.16

KS 1.105*** -0.000** 1 0 0.01

KY 1.410*** -0.001*** 0 0 0.15

MI 1.428*** 0.001*** -0.001* -0.001** -0.001* -0.001** -0.001*** -0.010*** 5 1 0.3

MN 1.890*** -0.001** -0.001* -0.001** -0.001** -0.001***-0.001***-0.001** -0.001** -0.001** -0.013***-0.008** -0.007** -0.008** -0.007* -0.008** -0.008** -0.007* 9 8 0.23

MO 1.292*** -0.001*** 0 0 0.29

MT 1.564*** 0.000*** -0.001* -0.001** -0.001** -0.002***-0.002***-0.001** -0.006*** 6 1 0.17

NE 1.846*** 0.000*** -0.001** -0.001** -0.001***-0.001***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002*** -0.008*** -0.010*** 11 2 0.33

NV 1.405*** 0.001*** 0.003* 0 1 0.29

NM 1.387*** 0.001*** -0.001** -0.001** -0.001** 0.011** 0.016*** 3 2 0.26

NY 1.523*** 0.001*** -0.001** -0.001* 2 0 0.1

ND 0.732*** -0.000*** 0.001** 0.000* 0.006*** 0.008*** 2 2 0.15

OH 1.415*** -0.001* -0.001** 0.006*** 2 1 0.05

OK 1.109*** -0.001*** -0.000** -0.000** -0.001*** -0.001***-0.001***-0.001***-0.000** 0.009*** 0.016*** 7 2 0.22

OR 1.473*** 0.003*** -0.014*** -0.010*** -0.012*** -0.014*** 0 4 0.65

PA 1.780*** 0.001*** -0.001** 1 0 0.12

SD 0.793*** 0.001*** 0.002*** 0 1 0.14

TX 0.898*** -0.001* -0.001* -0.001** 0.012** 0.015*** 3 2 0.05

UT 1.044*** 0.001*** 0 0 0.24

WA 2.372*** 0.002*** -0.014** -0.016** -0.030*** -0.024*** 0 4 0.29

WI 1.542*** -0.000* -0.001* -0.001* -0.001** -0.001** -0.001** -0.010*** -0.006** 5 2 0.11

WY 1.660*** 0.000*** -0.001* -0.001* -0.002** -0.002** -0.001** 6 0 0.11

Total 1 2 5 5 5 7 8 9 11 12 10 7 4 4 8 2 4 5 6 2 3 2 3 3
155

Table 7-2. Results of the stepwise regression of the hay (excluding alfalfa) price on current and eleven lagged values of PDSI

State Constant Trend PDSI PDSI(1) PDSI(2) PDSI(3) PDSI(4) PDSI(5) PDSI(6) PDSI(7) PDSI(8) PDSI(9) PDSI(10) PDSI(11) PDSI_max Rsq

AZ 1.160*** 0.003*** 0.018** 1 0.57

AR 1.024*** 0.001*** -0.026*** 1 0.12

CA 1.316*** 0.001*** -0.022*** 0.028*** 2 0.2

CO 1.399*** 0.001*** -0.046*** 1 0.4

ID 1.050*** 0.002*** 0 0.44

IL 1.155*** 0.000*** -0.026*** 1 0.1

IN 1.175*** 0.002*** 0.026** -0.054*** 2 0.16

IA 1.011*** 0.000*** -0.020*** 1 0.09

KS 1.080*** -0.007* 1 0.01

KY 1.390*** -0.001*** -0.019*** 1 0.18

MI 0.987*** 0.001*** 0 0.21

MN 1.053*** -0.032*** 1 0.07

MO 1.281*** -0.001*** -0.013*** 1 0.31

MT 1.160*** 0.001*** -0.038*** 1 0.13

NE 0.923*** 0.000*** -0.037*** -0.035*** 0.036*** 3 0.2

NV 1.472*** 0.001*** -0.022** -0.017* 2 0.32

NM 1.708*** 0.001*** -0.031*** -0.028*** 2 0.34

NY 1.303*** 0.001*** -0.013* -0.027*** -0.018** 3 0.21

ND 0.811*** -0.000*** -0.034*** 0.010** 2 0.17

OH 1.350*** -0.058*** 0.070*** 2 0.15

OK 1.200*** -0.000*** -0.029*** 0.025*** 2 0.15

OR 1.035*** 0.003*** 0.022*** 1 0.64

PA 1.658*** 0.001*** -0.034*** -0.024** 2 0.17

SD 0.807*** 0.001*** -0.022*** 1 0.17

TX 1.267*** -0.020* -0.021* 0.040*** 3 0.06

UT 1.034*** 0.001*** 0.010* 1 0.24

WA 1.665*** 0.002*** 0.031*** 1 0.27

WI 1.103*** -0.000** -0.034*** 0.026** 2 0.04

WY 1.374*** 0.000*** -0.024*** -0.048*** 0.026*** 3 0.18

Total 6 5 2 2 3 6 4 2 1 2 1 10
156

Table 7-3. Results of the nonlinear regression of the hay (excluding alfalfa) price on precipitation and temperature and neighboring states

State Constant Trend P P^2 NB_P NB_P^2 T T^2 NB_T NB_T^2 Rsq

AZ 2.667** 0.002*** 0.01 0 -0.025** 0.000* -0.197*** 0.004 0.16 -0.004 0.59

AR 16.796* 0 0.013 0 -0.013 0 -1.640*** 0.051 -0.349 0.012 0.05

CA -4.567 0.001*** -0.016*** 0.000*** -0.016*** 0 1.060*** -0.032 -0.206 0.004 0.29

CO 6.145*** 0.001*** -0.262*** 0.003*** 0.035** -0.000** 0.214*** -0.013** -0.189 0.009 0.54

ID 1.559* 0.001*** 0.009 0 -0.026** 0.000** -0.000*** -0.014 -0.025 0.011 0.5

IL -0.153 0 0.003 0 -0.058*** 0.000*** 1.156*** -0.047*** -0.517*** 0.020*** 0.28

IN 3.245 0.002*** -0.051 0 0.021 0 -3.120*** 0.136*** 3.120*** -0.141*** 0.3

IA 3.210*** 0.000*** -0.021** 0.000** 0.012 0 0.369*** -0.021 -0.694*** 0.036*** 0.25

KS 3.882** 0.000* -0.029*** 0.000*** 0.001 0 -0.748*** 0.028** 0.532*** -0.023*** 0.14

KY 3.078 -0.001*** -0.008 0 -0.051*** 0.000*** 0.240*** -0.006 -0.163 0.005 0.28

MI 5.213*** 0.002*** -0.015 0 -0.033 0 1.298*** -0.090*** -1.491*** 0.083*** 0.37

MN 0.963 -0.000** -0.01 0 0.024* -0.000* -0.325*** 0.007 0.207 0 0.26

MO -1.025 -0.001*** -0.008 0 -0.036*** 0.000*** 1.216*** -0.045*** -0.612** 0.024** 0.37

MT 3.580*** 0.001*** -0.057*** 0.000* 0.006 0 -0.830*** 0.053*** 0.545** -0.034* 0.3

NE 1.733** 0.000*** -0.109*** 0.001*** 0.028** -0.000** 0.230*** -0.017* 0.125 -0.004 0.43

NV 11.572*** 0.001*** 0.022*** -0.000** -0.061*** 0.000*** -1.596*** 0.091*** -0.119 -0.004 0.5

NM -8.312* 0.000*** -0.018*** 0.000*** 0.012 -0.000* 0.671*** -0.024 0.784*** -0.027*** 0.36

NY 0.442 0.001*** 0.057*** -0.000*** 0.01 0 0.699*** -0.054 -1.035 0.064 0.2

ND 0.783*** -0.000*** -0.022*** 0.000* 0.008 0 -0.379*** 0.028*** 0.392*** -0.023** 0.37

OH 5.210*** -0.001*** 0.053*** -0.000*** -0.132*** 0.001*** 0.343*** -0.002 -0.403 0.008 0.16

OK 8.269*** -0.001*** -0.007 0 0 0 -0.877*** 0.029** -0.05 0.004 0.29

OR 4.824*** 0.002*** 0.039*** -0.000*** -0.038*** 0.000*** -0.131*** 0.006 -0.530* 0.02 0.72

PA 0.673 0.001*** 0.001 0 0.02 0 0.005*** -0.001 0.067 -0.003 0.15

SD 0.774*** 0.001*** -0.069*** 0.001*** 0.042*** -0.000*** 0.220*** -0.022** -0.068 0.015* 0.31

TX 8.027 0 -0.025*** 0.000*** 0.009* 0 -0.731*** 0.024 -0.072 0.001 0.12

UT 3.060*** 0.001*** -0.054*** 0.001*** -0.004 0 0.264*** -0.016* -0.446*** 0.023*** 0.34

WA 4.891*** 0.002*** -0.073*** 0.000*** -0.032** 0 2.482*** -0.144*** -2.190*** 0.124*** 0.53

WI 2.803*** 0 -0.023 0 -0.008 0 0.439*** -0.028** -0.396** 0.016 0.13

WY 1.597* 0.001*** -0.02 0 -0.086** 0.001** -0.902*** 0.088*** 1.380*** -0.100*** 0.38
157

Table 7-4. Results of the nonlinear regression of the hay (excluding alfalfa) price on PDSI and neighboring states

State Constant Trend PDSI PDSI^2 NB_PDSI NB_PDSI^2Rsq

AZ 1.173*** 0.003*** 0.024** -0.008* -0.011 0.008* 0.57

AR 1.014*** 0.001*** -0.023*** 0.006* 0.022*** 0.001 0.15

CA 1.344*** 0.001*** 0.031** -0.009** -0.032* 0.003 0.21

CO 1.204*** 0.002*** 0.002 0.008** -0.008 0.047*** 0.48

ID 0.988*** 0.002*** -0.003 0.013*** 0.016 -0.009 0.46

IL 1.148*** 0.001*** -0.004 -0.004* -0.049*** -0.014*** 0.15

IN 1.192*** 0.001 -0.099*** 0.042*** 0.025 0.001 0.3

IA 1.028*** 0.000*** -0.032*** 0.003 0.011 -0.007 0.1

KS 1.085*** 0 0.015* -0.006** -0.030*** 0.011*** 0.06

KY 1.416*** -0.000*** -0.041*** 0.006** 0.022*** -0.017*** 0.24

MI 0.925*** 0.002*** 0.032*** -0.006 -0.096*** 0 0.28

MN 1.064*** 0 -0.060*** 0.022*** 0.013 -0.031*** 0.16

MO 1.312*** -0.001*** -0.023*** 0.012*** -0.008 0.016*** 0.37

MT 1.235*** 0.000*** -0.038*** 0.011*** -0.01 -0.027*** 0.17

NE 0.929*** 0.000** 0.004 -0.008*** -0.056*** 0.023*** 0.24

NV 1.395*** 0.001*** -0.037** 0.006 0 0.015** 0.37

NM 1.765*** 0.000*** -0.099*** 0.003 0.038*** -0.024*** 0.38

NY 1.335*** 0.001*** -0.044*** 0.007* -0.017 0.006 0.22

ND 0.826*** -0.000*** 0.002 -0.004* -0.039*** 0.015*** 0.2

OH 1.447*** 0 0.024*** -0.008*** -0.044*** -0.001 0.05

OK 1.199*** -0.001*** -0.008 0.008*** -0.016* -0.006 0.13

OR 1.043*** 0.003*** 0.099*** -0.011* -0.102*** 0.019** 0.67

PA 1.798*** 0.000*** -0.089*** 0.026*** 0.057*** -0.013** 0.23

SD 0.786*** 0.001*** -0.015 -0.008** -0.014 0.024*** 0.19

TX 1.253*** 0.000*** -0.040*** -0.005 0.030** -0.030*** 0.16

UT 1.063*** 0.001*** 0.106*** 0.018*** -0.131*** -0.016*** 0.4

WA 1.580*** 0.002*** 0.052*** 0.019*** -0.021 -0.004 0.29

WI 1.117*** -0.000*** -0.082*** 0.023*** 0.081*** -0.021*** 0.07

WY 1.292*** 0.000*** -0.071*** 0.035*** 0.014 -0.034*** 0.33
158

Table 7-5. Results of the stepwise regression of the alfalfa hay price on current and eleven lagged values of precipitation and temperature

State Constant Trend P P(1) P(2) P(3) P(4) P(5) P(6) P(7) P(8) P(9) P(10) P(11) T T(1) T(2) T(3) T(4) T(5) T(6) T(7) T(8) T(9) T(10) T(11) P_max T_max Rsq

AZ 1.438*** 0.001*** -0.001** 0.010*** 0.006** 1 2 0.3

AR 1.076*** 0.000** 0.002** 0 1 0.05

CA 1.892*** 0.001*** -0.008*** 0 1 0.16

CO 2.021*** 0.002*** -0.001* -0.001** -0.002** -0.002***-0.002** -0.002***-0.002***-0.002***-0.002** -0.005*** 9 1 0.54

ID 1.506*** 0.001*** -0.008** -0.012*** 0 2 0.32

IL 1.459*** 0.001*** 0.004*** 0 1 0.12

IN 1.681*** 0.002*** -0.001** -0.002***-0.001** -0.001** 0.013*** 4 1 0.27

IA 2.499*** 0.001*** -0.001* -0.001** -0.001* -0.001** -0.001***-0.001* -0.011** -0.010* -0.012** -0.017*** -0.013*** -0.013*** -0.013*** 6 7 0.2

KS 2.331*** 0.001*** -0.001** -0.001* -0.001** -0.001* -0.001** -0.001***-0.001***-0.001***-0.001* -0.001* -0.001** -0.011** -0.009* -0.008* -0.012*** 11 4 0.23

KY 1.629*** -0.000** -0.000* -0.001** 2 0 0.06

MI 1.830*** 0.001*** -0.001* -0.001* -0.001* -0.001* -0.001* -0.001** -0.001*** -0.012*** 7 1 0.29

MN 2.533*** -0.000** -0.001** -0.001***-0.001* -0.001***-0.001***-0.001** -0.001** -0.001** -0.001** -0.014***-0.014*** -0.009** -0.012** -0.011** -0.008* -0.008*? -0.010** 9 8 0.26

MO 1.261*** -0.001*** 0.005** 0.008*** 0 2 0.21

MT 1.780*** 0.000** -0.001 -0.002** -0.002***-0.002***-0.002***-0.002*** -0.007*** 6 1 0.14

NE 2.302*** 0.001*** -0.001***-0.001***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002***-0.002*** -0.011*** -0.009** -0.013*** 11 3 0.38

NV 1.711*** 0.001*** 0 0 0.15

NM 1.843*** 0.001*** -0.001** -0.001** -0.001** 0.010*** 0.016*** 3 2 0.26

NY 1.775*** 0.000*** -0.001* -0.001* 2 0 0.04

ND 1.015*** -0.000*** -0.005*** 0.004*** 0.010*** 0 3 0.08

OH 1.551*** -0.001*** 0.020*** 0.003 0.016*** 0 3 0.07

OK 1.745*** -0.001*** -0.001** -0.000* -0.001*** -0.001***-0.001***-0.001** -0.000* 0.010*** . 7 1 0.24

OR 1.722*** 0.002*** -0.007* -0.013*** 0 2 0.42

PA 2.061*** 0.000*** -0.001** 1 0 0.04

SD 1.044*** 0.001*** 0.002* 0 1 0.08

TX 1.423*** -0.000** -0.001* -0.001** -0.001** . -0.001** -0.001** -0.001** 0.014*** 0.009** 6 2 0.16

UT 1.376*** 0.001*** -0.003** 0 1 0.27

WA 2.633*** 0.002*** -0.022***-0.019*** -0.022***-0.022*** -0.017** -0.020*** 0 6 0.35

WI 2.038*** -0.001** -0.001*** -0.001* -0.002***-0.002***-0.001** -0.014*** 6 1 0.14

WY 1.713*** 0.001*** -0.002*** -0.001** -0.001* -0.002** -0.001* -0.002** 6 0 0.16

Total 0 2 5 7 7 9 10 13 12 11 11 10 6 6 6 3 4 4 4 8 4 4 5 3
159

Table 7-6. Results of the stepwise regression of the alfalfa hay price on current and eleven lagged values of PDSI

State Constant Trend PDSI PDSI(1) PDSI(2) PDSI(3) PDSI(4) PDSI(5) PDSI(6) PDSI(7) PDSI(8) PDSI(9) PDSI(10) PDSI(11) PDSI_max Rsq

AZ 1.620*** 0.001*** -0.028*** 0.034*** 2 0.2

AR 1.100*** 0.001*** -0.021*** 1 0.11

CA 1.748*** 0.001*** 0.035*** 1 0.15

CO 1.377*** 0.002*** -0.026*** -0.026** 0.037*** 3 0.5

ID 1.383*** 0.001*** 0 0.3

IL 1.489*** 0.001*** -0.016*** 1 0.11

IN 1.352*** 0.002*** 0.029** -0.057*** 2 0.18

IA 1.324*** 0.001*** -0.041*** 1 0.12

KS 1.297*** 0.001*** -0.021*** -0.025** 0.026*** 3 0.13

KY 1.495*** -0.029*** 1 0.07

MI 1.273*** 0.001*** 0 0.18

MN 1.476*** -0.000** 0.030** -0.031* -0.031** 3 0.09

MO 1.412*** -0.001*** -0.009* -0.013** 2 0.24

MT 1.328*** 0.000*** -0.037*** -0.034* 0.042** 3 0.08

NE 1.005*** 0.001*** -0.049*** -0.046*** 0.053*** 3 0.27

NV 1.717*** 0.001*** -0.025*** 0.015* 2 0.17

NM 2.193*** 0.000*** -0.038*** -0.033*** -0.027*** 3 0.39

NY 1.546*** 0.001*** -0.012* -0.024** -0.025** 3 0.17

ND 1.006*** -0.036*** 1 0.13

OH 1.945*** -0.000** -0.045*** 0.041*** 2 0.07

OK 1.513*** -0.001*** -0.029*** 0.036*** 2 0.18

OR 1.535*** 0.002*** 0.033*** 1 0.44

PA 1.926*** 0.001*** -0.045*** -0.023** 2 0.1

SD 1.049*** 0.001*** -0.030*** -0.025* 0.027** 3 0.14

TX 1.501*** -0.044*** 0.031*** 2 0.08

UT 1.334*** 0.001*** -0.012* 0.025*** 2 0.29

WA 1.609*** 0.001*** 0.025*** 1 0.27

WI 1.410*** -0.047*** 0.022* 2 0.04

WY 1.394*** 0.001*** -0.024** -0.028* -0.030* 0.041*** 4 0.21

Total 10 4 2 4 4 4 4 2 4 5 0 13
160

Table 7-7. Results of the nonlinear regression of the alfalfa hay price on precipitation and temperature and neighboring states

State Constant Trend P P^2 NB_P NB_P^2 T T^2 NB_T NB_T^2 Rsq

AZ -6.669 0 -0.005 0 -0.024** 0.000** 1.544*** -0.044 -0.566 0.018 0.29

AR 5.768 0 -0.003 0 -0.002 0 -0.381*** 0.01 -0.16 0.007 0.06

CA -4.22 0.001*** -0.019*** 0.000** 0.018 0 0.790*** -0.031 0.179 -0.008 0.18

CO 8.904*** 0.002*** -0.166*** 0.002*** 0.02 0 0.199*** -0.011* -0.764 0.027 0.61

ID 3.419** 0.002*** -0.039* 0 0.009 0 0.016*** -0.017 -0.272 0.022 0.37

IL -0.428 0.001*** -0.073*** 0.000*** 0.044* -0.000** 1.368*** -0.060*** -0.878*** 0.043*** 0.18

IN 10.776 0.001* -0.135*** 0.001** 0.073* 0 5.516*** -0.260*** -6.836*** 0.331*** 0.3

IA 7.742*** 0 -0.033*** 0.000*** 0.003 0 -0.811*** 0.024 -0.127 0.022 0.3

KS 4.556* 0.000*** -0.003 0 -0.107*** 0.001*** 0.698*** -0.017 -0.506 0.003 0.43

KY -0.551 -0.000*** 0.003 0 -0.032** 0.000*** 0.700*** -0.029 -0.247 0.015 0.15

MI 2.581** 0.001*** -0.004 0 -0.031 0 0.922*** -0.063** -0.656* 0.038 0.3

MN 2.305* -0.000* 0.065*** -0.001*** -0.085*** 0.001*** -0.527*** 0.022 0.398 -0.011 0.28

MO -1.752 -0.001*** -0.012 0 -0.031*** 0.000*** 1.193*** -0.043*** -0.453 0.016 0.29

MT 5.962*** 0.001*** -0.051** 0 0 0 0.199*** -0.022 -1.049** 0.076** 0.3

NE 2.35 0.001*** -0.133*** 0.001*** 0.001 0 0.071*** -0.007 0.509 -0.027 0.49

NV 2.872 0.000* -0.029*** 0.000*** -0.043*** 0.000*** -0.214*** 0.011 0.336 -0.018 0.25

NM -10.95* 0.000** -0.015** 0 -0.034* 0.000* 2.146*** -0.083** 0.144 -0.007 0.36

NY -2.939 0.001*** 0.04 -0.000* 0.001 0 -0.840*** 0.037 1.241 -0.049 0.17

ND 0.258 0 -0.051*** 0.000*** 0.068*** -0.001*** -0.433*** 0.040*** 0.425* -0.033* 0.27

OH -1.337 -0.000** -0.025 0 0.059 0 0.657*** -0.028 -0.359 0.016 0.08

OK -1.857 -0.001*** 0.024*** -0.000*** -0.041*** 0.000*** -0.272*** 0.012 0.930*** -0.039*** 0.32

OR -0.911 0.002*** -0.038*** 0.000*** 0.040*** -0.000*** -0.512*** 0.021*** 1.047*** -0.050*** 0.51

PA -0.055 0.001*** -0.072*** 0.000*** 0.120*** -0.001*** -1.122*** 0.054 1.182** -0.057** 0.1

SD 4.037*** 0.001*** 0.052** -0.001*** -0.117*** 0.001*** -2.147*** 0.112*** 2.211*** -0.126*** 0.38

TX 9.39 -0.000** -0.026*** 0.000*** -0.004 0 0.006*** 0.005 -1.033* 0.030* 0.18

UT 1.424 0.001*** -0.041*** 0.001*** -0.022 0 -0.153*** 0.006 0.414** -0.020** 0.37

WA 8.069*** 0.002*** -0.008 0 -0.018 0 -1.883*** 0.093** 0.908* -0.056* 0.41

WI 1.96 0 0.012 0 -0.060* 0.000* -0.328*** 0.045 0.787 -0.073 0.15

WY 3.258* 0.001*** -0.080*** 0.001*** 0.032 -0.001 -0.225*** 0.024 0.135 -0.019 0.36
161

Table 7-8. Results of the nonlinear regression of the alfalfa hay price on PDSI and neighboring states

State Constant Trend PDSI PDSI^2 NB_PDSI NB_PDSI^2Rsq

AZ 1.573*** 0.001*** -0.001 0.004 0.034*** 0.001 0.2

AR 1.103*** 0.001*** -0.018** -0.003 0.016** -0.01 0.12

CA 1.756*** 0.001*** 0.011 -0.011*** 0.038** 0.005 0.16

CO 1.290*** 0.002*** 0.013 0.002 -0.030** 0.014** 0.49

ID 1.282*** 0.002*** 0.001 -0.005 0.008 0.034*** 0.35

IL 1.490*** 0.001*** -0.006 -0.004 -0.018 0.003 0.11

IN 1.352*** 0.001* -0.088*** 0.037*** 0.023 0.016 0.32

IA 1.370*** 0.001*** -0.076*** 0.007 0.031* -0.016** 0.14

KS 1.295*** 0.001*** -0.012 -0.005 -0.014 0.012 0.11

KY 1.553*** 0 -0.046*** 0.009*** 0.008 -0.019*** 0.14

MI 1.248*** 0.001*** 0.028** -0.008** -0.081*** -0.007 0.23

MN 1.471*** 0 -0.081*** 0.026*** 0.029** -0.045*** 0.16

MO 1.430*** -0.001*** -0.044*** -0.012*** 0.015 0.023*** 0.29

MT 1.396*** 0 -0.047*** 0.015*** 0.012 -0.024*** 0.12

NE 1.012*** 0.000*** 0.009 -0.018*** -0.069*** 0.040*** 0.24

NV 1.660*** 0.001*** -0.059*** 0.004 0.066*** 0.005 0.2

NM 2.222*** 0.000*** -0.117*** 0.003 0.024 -0.017** 0.4

NY 1.556*** 0.001*** -0.045*** -0.006 -0.003 0.025*** 0.21

ND 1.026*** -0.000** -0.001 -0.005* -0.041*** 0.017*** 0.17

OH 1.956*** -0.000** 0.030*** 0.005 -0.081*** -0.005 0.08

OK 1.504*** -0.001*** 0.011 0.006* -0.029** 0.001 0.14

OR 1.491*** 0.002*** 0.101*** -0.007 -0.100*** 0.026*** 0.5

PA 2.071*** 0 -0.102*** 0.032*** 0.070*** -0.012** 0.18

SD 1.037*** 0.001*** -0.005 -0.008 -0.039* 0.020** 0.14

TX 1.511*** 0.000*** -0.046*** -0.008 0.023* -0.024*** 0.13

UT 1.368*** 0.001*** 0.092*** -0.006* -0.118*** 0.021*** 0.41

WA 1.540*** 0.002*** 0.026** 0.015*** 0.007 -0.005 0.29

WI 1.416*** 0 -0.074*** 0.016** 0.044** -0.023** 0.04

WY 1.355*** 0.000*** -0.078*** 0.037*** 0.026* -0.042*** 0.37
162

Mitigating forage replacement cost with a disappearing deductible

Given the relationship of forage yield to replacement forage prices, we investigated the potential to 

increase payments when a deep loss occurred. In other words, replacement cost is likely to be higher in a 

severe loss situation than in a less severe shortfall. Our team looked at mechanisms such as triggering 

higher payments when the grid is in drought region. Also, we considered some defined spatial region 

having a shortfall to trigger larger indemnities. All of these options have some merit. However, for the 

sake of simplicity, we opted for modifying the indemnity function by recommending a disappearing 

deductible. 

Disappearing deductibles were once a common option in property insurance in the United States, 

particularly for commercial policies. Although disappearing and franchise deductibles are still found in 

Europe, this method of risk sharing is now relatively rare in the United States, where the elimination of 

the deductible in the event of a large loss is generally not viewed as worth the additional premium 

required. 

The International Risk Management Institute, Inc. provides the following definition:

“Disappearing Deductible — a formula deductible that decreases as the amount of loss increases 

and disappears entirely to provide full coverage when the loss reaches a specified amount. 

Disappearing deductibles were once commonly used in property insurance policies.” 

Theory and Practice of Insurance describes the concept of a disappearing deductible:

“Besides the usual deductibles, the concept of disappearing deductible is often used for large business 

risks. Under a disappearing deductible, the size of the deductible decreases as the size of the loss 

increases. At a given level of loss (L*) the deductible is equal to zero (disappears). The formula to apply 

the reduction in the deductible (D) is the following: 

Compensation by the insurer = (Amount of loss – Deductible) x (1+k)

Where k is the adjusting factor:

 k = D / (L* - D)

and L* = D/k + D 

If the adjusting factor is fixed at 5% and the deductible is $1,000, then the deductible will disappear when 

the loss equals or exceeds $21,000. All losses under $1,000 are absorbed by the insured. On a loss of 

$15,000 the insurer would pay $14,700 (a $300 deductible).

Similarly, Cízek, Härdle, and Weron (2005) describe various types of deductibles, including franchise and 

disappearing deductibles:
163

Franchise Deductible 

One of the deductibles that can be incorporated in the contract is the so-called franchise deductible. In this 

case, the insurer pays the whole claim, if the agreed deductible amount is exceeded. More precisely, under 

the franchise deductible of , if the loss is less than the insurer pays nothing, but if the loss equals or 

exceeds claim is paid in full. This means that the payment function can be described as: 

Figure 7-1

STFded01.xpl

The payment function under the franchise deductible (solid blue line) and no deductible (dashed 

red line). 

The pure risk premium under the franchise deductible can be expressed in terms of the premium in the 

case of no deductible and the corresponding limited expected value function: 
164

It can be easily noticed that this premium is a decreasing function of . When the premium is 

equal to the no deductible case and if tends to infinity the premium tends to zero. 

Disappearing Deductible 

There is another type of deductible that is a compromise between the franchise and the fixed amount 

deductible. In the case of a disappearing deductible, the payment depends on the loss in the following 

way: if the loss is less than an amount of dd1 > 0, the insurer pays nothing; if the loss exceeds

 dd2 (dd2 > dd1) amount, the insurer pays the loss in full; if the loss is between dd1 and dd2 , then the 

deductible is reduced linearly between dd1 and dd2. Therefore, the larger the claim, the less of the 

deductible becomes the responsibility of the policyholder. The payment function is given by Figure 7.2 
165

Figure 7-2

The payment function under the disappearing deductible (solid blue line) and no deductible 

(dashed red line). 

The following formula shows the premium under the disappearing deductible in terms of the premium in 

the case of no deductible and the corresponding limited expected value function 

If dd1 = 0,, the premium does not depend on dd2 and it becomes the premium in the case of no 

deductible. If dd2tends to infinity, then the disappearing deductible reduces to the fixed amount deductible 

of dd1. 

 . 

Recommendation: Targeting Indemnities to make PRF a better risk 

management tool

Our review leads us to conclude that the current program frequently pays for shallow losses 
166

that are likely not significant financial threats while at times not sufficiently compensating 

for deep losses that are often a part of widespread droughts driving up replacement forage 

costs. We believe the program can become a better risk management tool. Based on the 

evidence we find a relationship between the replacement cost of forage and deep losses. We 

recommend dropping the maximum coverage level to 80 percent while also adding a 

disappearing deductible and adjustment to enhance indemnities when in an extreme loss 

situation. One could develop more elaborate drought triggers, but they add significant 

complexity. For the sake of operational simplicity, we believe the indemnity function should 

be in the form of a disappearing deductible and perhaps reflect an accelerated disappearing 

deductible. 

In the Pasture, Rangeland, Forage (PRF) Crop Provisions, section 5. (a) 

states:

5. Amounts of Protection and Coverage Levels

In lieu of section 7(a)(1) of the Basic Provisions, catastrophic risk protection is not available 

under these Crop Provisions. 

(a) In lieu of section 7(a)(2) of the Basic Provisions, for additional coverage policies, when 

available in the actuarial documents:

(i) You may select only one coverage level from 70 percent through 90 percent for the county, 

crop, intended use, irrigated practice, and organic practice; and Merely reducing the maximum 

coverage level without making further adjustments disadvantages the grower who previously 

elected higher coverage. The following graph illustrates indemnity levels for growers with 90

percent and 80 percent coverage:
167

Figure 7-3

0

5

10

15

20

25

30

35

100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0

Indemnity

Rainfall Index Value

Effect of Decreased Maximum Coverage Level

Absolute Loss (90%) Indemnity under decreased maximum
168

Figure 7-3

To illustrate the combination of decreased maximum coverage with a disappearing 

deductible consider a standard indemnity function 

CBV = $40 

Expected Index value = 100. 

Previous coverage level = 90% 

New maximum coverage level = 80%

Trigger level = Expected Index Value * Coverage level = 0.80

Final Index value = 0.50 

Previous coverage level indemnity = Maximum (prior trigger level – final index value) * 

Trigger level * CBV), 0) = (0.9 – 0.5) * $40 = 0.4 * $36 = $16.00 

Absolute Deductible Indemnity with new maximum coverage level = Maximum ((trigger 

level – final index value) * Trigger level * CBV), 0) = (0.8 – 0.5) * 0.8 * $40 = 0.3 * $32 = 

$9.60 

0

5

10

15

20

25

30

35

40

45

100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0

Indemnity

Rainfall Index Value

Alternative Linear Indemnity Functions 

Absolute Loss (90%) Indemnity under decreased maximum

Disappearing Deductible Modified Disappearing Deductible
169

Conversely a disappearing deductible could be targeted to gradually eliminate the deductible 

as the loss increases:

Disappearing Deductible Indemnity = Maximum (((trigger level – final index value))/ trigger 

level * CBV), 0) = 0.375 * $40 = $15 

Or, a modified Disappearing Deductible could simply return the producer to the same level 

of coverage desired (90%) once coverage is triggered (80%):

Modified Disappearing Deductible Indemnity = $0 when final index < new maximum 

coverage level, otherwise previous coverage level indemnity 

In the extreme case of a rainfall index equal to zero

Absolute Deductible Indemnity = Maximum ((trigger level – final index value) * Trigger 

level * CBV), 0) = 1.0 * $32 = $32.00 

Disappearing Deductible Indemnity = Maximum (((trigger level – final index value))/ trigger 

level * CBV), 0) = 1.0 * $40 = $40 

Linear approaches to making up the gap in coverage due to the decreased maximum 

indemnity may still overcompensate the grower in the event of relatively shallow losses. We 

note that the disappearing deductible function does not necessarily need to follow a linear 

function as shown above. It can be scaled to provide more coverage in the event of deeper 

losses using an exponent. Extending our example: 

Non-linear disappearing deductible 

Scaling exponent = 1.25

Non-linear Deductible Indemnity = Maximum (((trigger level – final index value)) ^ scaling 

exponent / trigger level * CBV), 0) = 0.375 ^ 1.25 * $40 = $11.70 

Another approach is to speed up the loss function such that maximum indemnity is reach 

when the total factor loss is reached. This approach is described in Martin, Barnett, and 

Coble (2001). 
170

Figure 7-4

Chapter 7 References:

J. François Outreville (1998), Theory and Practice of Insurance, Springer Science+Business Media, page 

136. 

https://books.google.com/books?id=YfAHCAAAQBAJ&pg=PA136&lpg=PA136&dq=disappearing+ded

uctible+formula&source=bl&ots=hCq-fKPIuM&sig=ACfU3U03s9VIwNC4LyfvfmvZHaObR2iEA&hl=en&sa=X&ved=2ahUKEwib4KPniOToAhUDEqwKHThvBQoQ6AEwE3oECA8

QKA#v=onepage&q=disappearing%20deductible%20formula&f=false

Pavel Cízek, Wolfgang Härdle, Rafa Weron, Statistical Tools for Finance and Insurance, 

ebooks, Xplore-Stat.de., http://sfb649.wiwi.huberlin.de/fedc_homepage/xplore/ebooks/html/stf/stfhtmlnode120.html

 

0

5

10

15

20

25

30

35

40

45

100 95 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 10 5 0

Indemnity

Rainfall Index Value

Non-linear Indemnity Function Example 

Absolute Loss (90%) Indemnity under decreased maximum

Disappearing Deductible Non-linear disappearing deductible
171

Appendix 1: Summary of CBV Calculation Steps

Non-irrigated Haying CBV Calculation

A. Calculate non-irrigated hay yield (in tons/acre)

1. Take the 10-year average of the most recent state-level NASS non-irrigated “all hay” yield data:

10

10

1

1

10 State i

i

AHY AHY =

= ∑ , 

where: 10 AHYState is the 10-year state-level average non-irrigated yields, and AHYi is the NASS 

state-level non-irrigated “all hay” yield in the year i. 

2. Calculate the non-irrigated haying factor (NHF) from the FRIS data on non-irrigated hay yields ( F NHY ) and “all hay” yields ( F AHY ): 

F

F

NHY NHF

AHY = . 

3. Multiply NHF to the 10 AHYState to get the state-level non-irrigated hay yield ( 10 NHYState ):

10 10 NHY NHF AHY State = × State . 

4. From the NRCS HPM, derive percent difference between district-level and state-level net primary 

productivities (NPP), which we call the NPP district-state factor (NDSF).

 

5. Multiply NDSF to the 10 NHYState to get the district-level non-irrigated hay yield value ( 10 NHYDistrict

) in tons/acre: 10 10 NHY NDSF NHY District State = × . 

B. Calculate non-irrigated hay price (in $/ton) 

1. Take the 3-year average of the most recent NASS “all hay, excluding alfalfa” price data:

3

3

1

1

3 State i

i

HP HP == ∑ . 

where: 3 HPState is the 3-year average state-level non-irrigated hay price, and HPi is the NASS “all 

hay, excluding alfalfa” price in year i. 

2. For certain states (with predominantly irrigated hay production), a regional average of 3 HPState for 

the Plain states are used. 

C. Calculate the non-irrigated hay CBV (in $/acre)

1. Multiply 10 NHYDistrict with 3 HPState to get the non-irrigated hay CBV estimate ( NIH CBV ) at the 

district-level:
172

NIH 10 3 CBV NHY HP District State = × . 

Irrigated Haying CBV Calculation

1. Collect data from FRIS on state-level irrigation cost (per acre inch) ( State

s IC ) by different irrigation 

source s. 

2. Take the weighted average of State

s IC to get an overall estimate of the average state-level irrigation 

cost (per acre inch) ( State IC ): ( )

1

1 s State State

s s

s

IC IC

s

γ

=

= × ∑ where s γ is the weight by source.

3. Multiply State IC to the inches of rainfall (R) at the grid-level to get the irrigated haying CBV 

( ) IH CBV in $/acre: IH State CBV IC R = × . 

Grazing CBV Calculation

A. Calculate grazing yield (in tons/acre)

1. Collect yearly pasture rental rate ($/acre) and grazing rate ($/AUM) data at the state level.

2. Calculate the 10-year average of the most recent NASS state-level pasture rental rate (PR) and 

grazing rate (GR) data:

10

10

1

1

10 State i

i

PR PR == ∑ and 

10

10

1

1

10 State i

i

GR GR == ∑ . 

3. Estimate the average forage consumption (or the forage “harvested” by livestock) that is an 

estimate of grazing yield ( AUM GYState )in AUM/acre by dividing 10 PRState by 10 GRState : 

10

10

AUM State

State

State

PR GY

GR = . 

4. Multiply AUM GYState by the AUM-Ton conversion factor (ATCF) (where ATCF = 0.47 tons/AUM) 

to get an estimate of the grazing yield in tons/acre (GYState ):

AUM GY GY ATCF State State = × . 

B. Calculate grazing price (in $/ton) 

1. Calculate 3-year averages for the most recent yearly state-level grazing rates (GR) in $/AUM and 

most recent NASS “all hay, excluding alfalfa” price (HP) data in $/ton: 

3

3

1

1

3 State i

i

GR GR == ∑ and 

3

3

1

1

3 State i

i

HP HP == ∑ . 
173

2. Convert 3 GRState to its $/ton equivalent by dividing 3 GRState by the ATCF: 

3 GR GR ATCF State State = × . 

3. Calculate the “blended” grazing price (BGP) in $/ton by taking the ave. of GRState and 3 HPState : 

( ) 1 3

2

BGP GR HP State = + State State . 

C. Calculate the grazing CBV (in $/acre)

1. Calculate the state-level grazing CBV ( G CBVState ) by multiplying GYState and BGPState : 

G CBV GY BGP State State State = × . 

2. From the NRCS HPM, derive NPP county-state factor (NCSF) by taking the ratio of the countylevel NPP and the state-level NPP.

3. Compute the county-level grazing CBV ( G CBVCounty ) by multiplying G CBVState with the NCSF: 

G G CBV CBV NCSF County = × State . 

4. For each agricultural district in the state, the district-level grazing CBV ( G CBV ) used in the 

PRF contract is derived by taking the average of the county-level grazing CBVs from the counties 

that comprise each district: 

,

1

1 n G G

County i

i

CBV CBV

n =

= ∑ . 
174

Appendix 2 Price Yield Relationship

To evaluate the extent to which a relationship exists between yield, price, precipitation, and 

temperature, we collected hay (alfalfa and all classes) prices and yields from NASS. In light 

of likely changes in the technology associated with pasture and forage production, we 

limited our analysis to the period spanning 1980-2018. Prices and weather (precipitation 

and temperature) were observed monthly. Yields were only available on an annual basis 

and thus the yield data were compared to annual aggregates of precipitation and 

temperature. Temperature data are reported for the maximum temperature, the minimum 

temperature, and the average temperature. 

Figure A1 to A5 illustrates the relationship between price changes (given as the log of the 

ratio of price to the previous year’s price in the same month). Figure A2 considers the 

change in precipitation relative to the previous month. Linear regression lines were 

included in the evaluation to consider whether any simple relationships between yields, 

prices, and the various weather variables were obvious. None were found. Given the 

limited data available on pasture, hay, and forage yields and prices, we were unable to 

discern any significant relationship between prices, yields, and weather. Although the 

relevant agronomic/rangeland literature has noted the importance of both temperature and 

precipitation to pasture and range health, our analysis does not reveal any relationships that 

might prove helpful in establishing a payoff schedule based upon precipitation and 

temperature. 
175

Figure A1. Precipitation and Price Change from Previous Year 
176

Figure A2. Precipitation and Price Change from Previous Month 
177

Figure A3. Maximum Temperature and Price Change from Previous Year 
178

Figure A4. Minimum Temperature and Price Change from Previous Year 
179

Figure A5. Average Temperature and Price Change from Previous Year
180

Appendix 2 Station IDs With LCC 8/U > 50% of Land Area

FIPS Codes FIPS Codes

4001 22051

4003 22057

4007 22075

4009 22087

4012 22089

4015 22095

4021 22101

8009 22109

8079 34017

8099 35028

12087 35031

13051 35049

16037 36085

16081 38075

20071 44001

20075 46035

20171 46061

20187 46119

20203 48383

22023
181

Appendix 3 Station IDs With Forage Production < 1st Percentile

Station Station

ID Latitude Longitude ID Latitude Longitude

14763 32.375 -114.375 19854 36.625 -116.625

14764 32.375 -114.125 19858 36.625 -115.625

15361 32.875 -114.875 19859 36.625 -115.375

15660 33.125 -115.125 20150 36.875 -117.625

15661 33.125 -114.875 20151 36.875 -117.375

15957 33.375 -115.875 20450 37.125 -117.625

15958 33.375 -115.625 20451 37.125 -117.375

15959 33.375 -115.375 20452 37.125 -117.125

15960 33.375 -115.125 20453 37.125 -116.875

15961 33.375 -114.875 20751 37.375 -117.375

16260 33.625 -115.125 21050 37.625 -117.625

16261 33.625 -114.875 21051 37.625 -117.375

16559 33.875 -115.375 21052 37.625 -117.125

16560 33.875 -115.125 21053 37.625 -116.875

16561 33.875 -114.875 21054 37.625 -116.625

16857 34.125 -115.875 21055 37.625 -116.375

16858 34.125 -115.625 21348 37.875 -118.125

16859 34.125 -115.375 21349 37.875 -117.875

16860 34.125 -115.125 21350 37.875 -117.625

16861 34.125 -114.875 21351 37.875 -117.375

16862 34.125 -114.625 21352 37.875 -117.125

17156 34.375 -116.125 21353 37.875 -116.875

17157 34.375 -115.875 21648 38.125 -118.125

17158 34.375 -115.625 21649 38.125 -117.875

17159 34.375 -115.375 21650 38.125 -117.625

17160 34.375 -115.125 21651 38.125 -117.375

17455 34.625 -116.375 21652 38.125 -117.125

17456 34.625 -116.125 21948 38.375 -118.125

17457 34.625 -115.875 21949 38.375 -117.875

17756 34.875 -116.125 21950 38.375 -117.625
182

18054 35.125 -116.625 21951 38.375 -117.375

18055 35.125 -116.375 21957 38.375 -115.875

18056 35.125 -116.125 21976 38.375 -111.125

18356 35.375 -116.125 21977 38.375 -110.875

18654 35.625 -116.625 22247 38.625 -118.375

18655 35.625 -116.375 22276 38.625 -111.125

18656 35.625 -116.125 22277 38.625 -110.875

18676 35.625 -111.125 22546 38.875 -118.625

18954 35.875 -116.625 22547 38.875 -118.375

18975 35.875 -111.375 22548 38.875 -118.125

19260 36.125 -115.125 22580 38.875 -110.125

19287 36.125 -108.375 22846 39.125 -118.625

19549 36.375 -117.875 23445 39.625 -118.875

19551 36.375 -117.375 23745 39.875 -118.875

19553 36.375 -116.875 23746 39.875 -118.625

19554 36.375 -116.625 23747 39.875 -118.375

19852 36.625 -117.125 24366 40.375 -113.625

19853 36.625 -116.875 24367 40.375 -113.375