United States 

 Department of 

 Agriculture

 National 

 Agricultural 

 Statistics 

 Service

 Research and 

 Development Division 

 Washington DC 20250 

 RDD Research Report 

 Number RDD-06-01 

 March 2006 

Using Personal Digital 

Assistants for the 

2004 Cotton Objective 

Yield Survey

Kathy Neas 

Jubal Molina 

Jason Hardegree 

Michael W. Gerling 

This paper was prepared for limited distribution to the research community outside the United States 

Department of Agriculture. The views expressed herein are not necessarily those of the National 

Agricultural Statistics Service or of the United States Department of Agriculture. 

i 

EXECUTIVE SUMMARY 

In the fall of 2003, the North Carolina Field Office (NC FO) and the Research and Development 

Division studied the use of personal digital assistants (PDAs) for the 2004 Cotton Objective 

Yield Survey (COY). The NC field enumerators were provided with PDAs to record COY data 

on them instead of on paper forms. The goals of the study were to develop a user-friendly data 

collection instrument to operate on a PDA which field enumerators could successfully record 

COY data into and securely transmit the data to the NC FO. This project also investigated if 

using PDAs would improve the data collection process, provide the collected data to the office 

staff quicker, improve data quality, and be cost effective. 

The NC FO developed a process for field enumerators to collect COY data using PDAs. Each 

NC FO field enumerator team (composed of two people) was supplied with a PDA. Training 

went fairly smoothly, despite the fact that the majority of field enumerators had never used a 

computer prior to the training session. Data collection was virtually problem-free. Data 

transmission, however, had some problems. If PDA data collection use continues, the data 

transmission process will require streamlining, while at the same time maintaining NASS 

security standards. After the data collection phase, field enumerators stated that they would 

prefer a device that could handle dirt and rain. Overall, the field enumerators were able to record 

the data onto the PDA and securely transmit the data to the field office for processing. 

The project demonstrated that PDAs can successfully be used by field enumerators for the 

Cotton Objective Yield Survey. 

ii 

RECOMMENDATIONS 

1. Recommend the North Carolina Field Office continue to explore the use of personal 

digital assistants (PDAs) for field data collection and administrative activities. 

2. Improve field office tracking of office staff time and costs related to implementing PDAs 

for data collection for subsequent years following the initial investment. 

3. Recommend that micro-level, interactive editing tools be created to clean the data more 

efficiently prior to the mainframe edit. Using PDAs provided data faster which revealed 

the need for these enhanced processing tools. 

1

Using Personal Digital Assistants For The 2004 Cotton Objective Yield 

Survey1

Kathy Neas, Jubal Molina, 

Jason Hardegree, Michael W. Gerling 

 

Abstract 

The National Agricultural Statistics Service (NASS) conducts hundreds of 

surveys (annually, monthly and in some cases weekly) on United States and 

Puerto Rico agriculture for the purpose of making estimates on crops, livestock, 

production practices, economics, etc. One of the monthly surveys is the Cotton 

Objective Yield Survey. Field enumerators typically record the data for this 

survey on paper forms and mail them to the field office for processing. The 

collected survey data allow NASS to forecast cotton yields and determine the 

amount of acreage to be harvested. 

In the fall of 2003, NASS’ North Carolina Field Office and the Research & 

Development Division combined efforts to explore the use of personal digital 

assistants (PDAs) in place of the paper forms. 

The goals of the study were to develop a user-friendly data collection instrument 

to operate on a PDA which field enumerators could successfully record COY data 

into and securely transmit the data to the NC FO. The project also investigated if 

using PDAs would improve the data collection process, provide the collected data 

to the office staff quicker, improve data quality, and be cost effective. 

Key Words: Data Collection, Agriculture, PDA

 

1

 Kathy Neas (Agricultural Statistician), Jubal Molina (Computer Specialist), Jason Hardegree 

 (Agricultural Statistician) are with the National Agricultural Statistics Service – North Carolina 

 Field Office, located at 2 W. Edenton Street, Raleigh, NC 27767. Michael W. Gerling 

 (Mathematical Statistician) is with the National Agricultural Statistics Service - Research & 

 Development Division, located at Room 305, 3251 Old Lee Highway, Fairfax, VA 22030. 
2

1. INTRODUCTION 

The National Agricultural Statistics 

Service’s (NASS) mission is to provide 

timely, accurate and useful statistics on United 

States and Puerto Rico agriculture. To 

accomplish this purpose, NASS conducts 

hundreds of surveys on agriculture (crops, 

livestock, production practices, farm 

economics, etc). 

 The Cotton Objective Yield Survey 

(COY) is conducted monthly beginning in 

July and continues through cotton harvest. 

Historically, field enumerators have recorded 

the survey data on paper forms and mailed 

them to NASS Field Offices for processing. 

In the fall of 2003, NASS’ North 

Carolina Field Office (NC FO) and the 

Research & Development Division (RDD) 

started to explore the use of personal digital 

assistants (PDAs) to replace the paper forms. 

The goals of the study were to develop 

a user-friendly data collection instrument to 

operate on a PDA which field enumerators 

could successfully record COY data into and 

securely transmit the data to the NC FO. The 

project also investigated if using PDAs would 

improve the data collection process, provide 

the collected data to the office staff quicker, 

improve data quality, and be cost effective. 

2. WHY RESEARCH PORTABLE 

ELECTRONIC DEVICES FOR 

DATA COLLECTION NOW? 

 

NASS actively seeks ways to improve 

its business practices to gain efficiencies in 

data collection and improve the quality of its 

data products. 

In the early 1990s, the laptop was the 

primary option in the portable electronic 

devices (PEDs) market. However, over the 

last seven years, personal digital assistants, 

tablet PCs, convertibles, Web pads, and smart 

phones have become more readily available 

and are now being used by private companies 

and government agencies for data collection 

and daily business activities. 

NASS has a history of research into 

the use of portable electronic devices in data 

collection (Eklund 1991, 1993, 1994). In the 

late 1980s and early 1990s, computer assisted 

personal interview (CAPI) research projects 

proved that data could be successfully 

collected using laptop computers and 

transmitted to a central location for further 

processing. At the time, several barriers 

prevented adoption of this technology into 

NASS’ operational program. Among these 

were battery life, data transmission speeds, 

cost of the laptops, and the limited number of 

field enumerated surveys for which they could 

be used. 

Since NASS first researched PEDs in 

the 1980s, technological advancements have 

been made in the area of CAPI. Data 

transmission speed and battery life have 

improved. At the same time, prices of PEDs 

have been decreasing, even as the devices are 

becoming more powerful (Gerling 2004). 

In the summer of 2002, the NC FO 

conducted a State Fair Climate Survey. As 

part of the agreement with the North Carolina 

State Department of Agriculture, PDAs were 

provided to collect the data. The NC FO 

designed a data collection instrument and 

successfully used the PDAs to conduct the 

survey. This success caused the NC FO to 

look beyond the state fair survey to additional 

data collection and administrative 

applications. 

Hence, in the fall of 2003, the NC FO 

and the RDD began investigating the use of 

personal digital assistants for the Cotton 

Objective Yield Survey. 
3 

3. COTTON OBJECTIVE YIELD 

SURVEY OVERVIEW 

The Cotton Objective Yield Survey 

Program began in the late 1950s. The 

survey’s purpose is to provide accurate data to 

forecast cotton yields and the amount of 

cotton acreage harvested in the United States. 

Yields are forecast by modeling recorded 

plant counts and measurements from sampled 

field units.

Cotton fields are statistically sampled 

from data collected by NASS’ June 

Agricultural Survey. The COY is composed 

of four forms (A, B, C and E). Forms A, B, 

and E are completed by the field enumerators 

while Form C is completed by office staff. 

Form A is completed during the initial 

interview with the operator, while Form B is 

completed monthly until the cotton is 

harvested. Form E is completed after the 

cotton is harvested in the sampled fields. This 

study, however, focused only on Form B, the 

form used for the monthly plant counts and 

measurements. 

The sample plot in each sampled 

cotton field is composed of two units. Unit 1 

is physically located by a pre-determined 

number of rows and paces inside the sampled 

field. Unit 1 is composed of two sections of 

rows located beside each other. These 

sections are 13 feet and 10 feet in length. Unit 

2 is also physically located by a predetermined number of rows and paces in the 

same field. Unit 2 is also composed of two 

sections as described for Unit 1. 

Starting in July, and continuing 

through October, or until the crop is harvested, 

enumerators return to the units each month to 

make plant and fruit counts of the cotton 

plants within the units and record findings on 

a Form B. These forms are then mailed to the 

field office where the data are reviewed, 

keyed, edited and analyzed. 

4. PERSONAL DIGITAL 

ASSISTANTS 

Personal digital assistants, commonly 

called PDAs, are mini-computers used to keep 

track of appointments, read e-mail, and review 

documents. Typically, PDAs are about 4 - 5.5 

inches long, about three inches wide and 0.5 

to 1 inch deep. This small size, combined 

with a weight of only 4 to 7 ounces, makes the 

device easy to handle. Data input typically 

occurs by the use of a stylus, (pen-like writing 

instrument used for data entry and screen 

navigation). Figure 1 shows a picture of a 

typical PDA and stylus (not to scale). 

Figure 1: 

 

5. WHY COTTON OBJECTIVE 

YIELD SURVEY? 

The Cotton Objective Yield Survey 

was selected for field-testing PDA data 

collection for several reasons. 

First, the COY is a survey that requires 

field enumeration. 

 Second, since this was the first time 

PDAs would be used to collect field data, a 
4 

questionnaire with relatively few pages was 

desired. Being only two pages, Form B fits 

this criterion. See Appendix A for a copy of 

the COY Form B. 

Third, the paper version of Form B 

does not contain any questions displayed in a 

table format. In general, tables cannot be fully 

displayed on a PDA’s small screen. 

 Fourth, the Form B is used month after 

month for the enumeration period, July 

through cotton harvest. This allowed the 

developer to focus on developing and testing 

one data collection form. 

One additional factor was that the data 

being collected don’t require any contact with 

the farm operator. Hence, if any problems 

occurred with the PDA, the enumerator could 

correct the problems without feeling rushed by 

the farm operator. 

A data collection instrument for Form 

A was constructed but, due to time constraints, 

wasn’t able to be tested and therefore wasn’t 

used. 

6. HARDWARE

Hewlett Packard (HP) PDAs were 

selected because the North Carolina FO 

already had ten HP iPAQ 3850 PDAs from the 

State Fair Climate Survey Project. Using 

similar hardware from the same company 

allowed the data collection instrument and 

data security to be designed around one 

platform. However the HP iPAQ 3850 was 

no longer available, so eight HP iPAQ 2210s 

were purchased so that each enumerator team 

was equipped with a PDA. The iPAQ 2210 

was the least expensive and most comparable 

model to the iPAQ 3850 at the time. The term 

iPAQ, a registered trademark of HP, is used 

throughout the rest of the paper to denote the 

PDA being utilized in the project. 

CompactFlash telephone modems were 

purchased so that the PDAs could transmit 

data over telephone lines through the NASS 

Access Server to the field office. The NASS 

Access Server is used for secure dial-up 

access to NASS computer systems; for this 

project it allowed enumerators to transmit data 

to and from the NC FO local area network. 

Also, rugged cases were purchased for eight 

of the PDAs to protect them from the 

elements. 

Table 1 shows the breakdown of the 

hardware used for the COY project.

Table 1: Hardware Utilized

Hardware Number 

HP iPAQ 3850 10 

HP iPAQ 2210 8 

CompactFlash Telephone 

Modems 

18 

Rugged Cases 8 

Stylus (Extra) 10 

7. SOFTWARE 

Visual Basic was chosen as the 

programming language for the data collection 

instrument since the software is compatible 

across iPAQ and PC platforms, and the NC 

FO had a computer specialist experienced 

with Visual Basic. 
5 

Encryption was necessary to ensure 

confidentiality of the data. The software 

Sentry 20/20 was selected because it was 

inexpensive, compatible with the iPAQ’s 

platform and allowed the data to be encrypted 

and password protected. Eighteen copies were 

purchased, one for each iPAQ. A host copy of 

Sentry 20/20 was also purchased to provide 

the NC FO the capability to decrypt the 

transmitted data. 

Each of the iPAQs was also password 

protected to ensure data security in case of 

theft or loss. 

To transfer data from the field to NC 

FO’s server, File Transfer Protocol (FTP) 

client software was required. FTP is the 

standard format for exchanging files over the 

Internet. In general, FTP is the process one 

uses to upload files to or download files from 

a server. Scotty FTP was selected because the 

software worked well in the iPAQ 

environment. 

Slim Pocket and CedeFTP were also 

tested but both products had some 

functionality problems and were more 

cumbersome than Scotty FTP. 

Dot Pocket was purchased for 

controlling the iPAQs through a PC, 

developing the data collection instrument, and 

for training purposes. Dot Pocket also 

allowed the developer to view the data 

collection instrument on a desktop computer, 

which made it easier for development and 

demonstrations.

Table 2 shows the software and 

number of copies utilized for the study. 

Table 2: Software 

Software Number of Copies 

Visual Basic 1 

Sentry 20/20 18 

Sentry 20/20 Host 1 

Scotty FTP 18 

Dot Pocket 1 

8. DATA COLLECTION 

INSTRUMENT

As noted earlier, Visual Basic was the 

development software selected to build the 

data collection instrument. The instrument 

followed the paper form as closely as possible. 

Skip logic on the paper form was included in 

the instrument. Edits were included to check 

the validity of the data at the point of 

collection and thereby reduce enumerator 

errors and improve data quality. 

The instrument was initially tested on 

a desktop computer before being placed on the 

iPAQ. 

 To access the programs on the iPAQ, 

the enumerator had to enter his/her username 

and password. After logging in, the 

enumerator’s ID and his/her supervisory 

enumerator’s ID, which were pre-stored on the 

iPAQ, as well as the date and time were 

automatically captured with the data being 
6 

collected. Figures 2, 3 and 4 show 

screenshots of the instrument as it appears on 

the iPAQ. 

Figure 2: After the enumerator successfully 

logs into the iPAQ, the following screen 

appears, allowing the enumerator to access 

Form B. 

Figure 3: Form B’s Unit Location Code 

Question. 

Figure 4: Enumerator uses the on-screen 

number pad to enter the value of the answer of 

the question.
7 

With the data collection instrument 

being new, some bugs were detected after 

deployment. The NC FO staff had to 

troubleshoot some of these problems without 

seeing the iPAQs and only relying on the 

enumerator’s words. Afterwards, the NC FO 

suggested that software to remotely access the 

enumerator’s iPAQ would have helped by 

visually seeing the problem on the iPAQ. 

9. TRAINING

From the start, the NC FO realized that 

many of the field enumerators had little or no 

computer experience. To better prepare the 

field enumerators, the NC FO staff introduced 

a prototype of the data collection instrument to 

the supervisory field enumerators in January 

of 2004. The data collection instrument was 

later modified based on the feedback received 

from these supervisory field enumerators. 

 In May of 2004, a four-hour PDA 

training session was held with the twenty-two 

COY field enumerators and supervisors. The 

data collection instrument programmer and the 

statistician supervising COY demonstrated the 

latest version of the instrument and updated 

the instrument based on the enumerators’ 

comments. 

 During July 8-9, 2004, the survey 

training workshop was conducted for the 

Cotton Objective Yield Survey. 

The morning of the first day was spent 

reviewing procedures to complete the various 

COY forms and visiting a nearby cotton field 

to practice laying out sample units. In the 

afternoon, training focused on using the 

iPAQs. Since the NC FO field enumerators 

work in pairs for COY, each pair was supplied 

with an iPAQ. The instructor quickly 

discovered that computer technology terms 

with which he was very familiar, such as 

‘mounting and dismounting the volume’ and 

‘synching up’, were well beyond his 

audience’s experience and knowledge level. 

He was then able to make his presentation less 

technical so that non-computer users could 

easily comprehend. Initially, the field 

enumerators had difficulty entering their 

passwords. Those who had never used a 

computer were, at times, lost and became a 

little frustrated. This was due to unfamiliarity 

with using a stylus. 

 On the second day, the field 

enumerators returned to the same cotton field 

and used the iPAQs to collect practice data. 

Those who continued to have problems using 

the stylus were eventually able to enter the 

data successfully into his/her iPAQ. 

After the field exercise, each pair of 

enumerators was scheduled to practice 

transmitting their collected data back to the 

NC FO. This required the enumerator to log 

into the NASS Access Server over the 

telephone line. However, the server was not 

functioning at the time. Hence, a hardcopy of 

the instructions was reviewed in place of the 

live practice. 

Along with the formal training, 

enumerators were provided handouts that 

covered daily instructions, transmission 

instructions, and troubleshooting tips. 

Instructions for downloading updates to the 

iPAQ were also provided in case a problem 

was found with the data collection instrument. 

In such an event, the NC Field Office could 

update the software instrument and place this 

update on the field office’s server for the 

enumerators to access and download. 

Separate instructional handouts for the 

HP 3850 and HP 2210 were developed to 

accommodate each model. Appendix B 

contains a copy of the data transmission 

instructions for the HP 3850. 

Overall, enumerators felt that the 

training workshop was informative. Most felt 

that as their experience with the iPAQs 
8 

increased, their comfort level with the iPAQs 

would improve. Enumerators appreciated the 

step-by-step instructions and wanted more 

troubleshooting scenarios included. 

A week after the enumerator 

workshop, the NASS Access Server’s problem 

was corrected. This allowed the NC FO staff 

to conduct three mini-training sessions to 

demonstrate how to transmit data. After the 

training, each enumerator was able to 

successfully transmit data. 

10. FIELD DATA COLLECTION

Twenty-two field enumerators used the 

iPAQs for field data collection. Enumerators 

worked in pairs for collecting COY data. The 

COY sample size was 120. 

11. DATA TRANSMISSION FROM 

THE FIELD TO THE OFFICE

First, enumerators charged the 

batteries on their PDAs. This was to avoid the 

PDA going into “hibernation” mode to save 

battery life. During “hibernation” mode, the 

screen darkens and the enumerator is unable to 

track the transmission. Second, they inserted 

the provided CompactFlash telephone modem 

into the iPAQ, connected a working telephone 

line to the modem, and restarted the iPAQ. 

Third, they connected to the NASS Access 

Server and accessed the iPAQ’s FTP client 

software. Last, they uploaded the data to the 

NC FO’s Server. 

 During several days, due to problems 

with the NASS Access Server, data 

transmission was not possible. The problem 

was resolved by replacing the server with a 

newer model. 

 Sometimes enumerators evoked a 

lock-out on the NASS Access Server by 

entering an incorrect password multiple times. 

This required personnel from NASS’ 

Information Technology Division to reset the 

password. 

Occasionally, an enumerator would 

also enter an incorrect password and thus lock 

himself/herself from gaining access to the NC 

FO server. This required the NC FO to 

manually unlock the enumerator’s account. 

 Some enumerators were overwhelmed 

by the number of steps required to transmit 

data. For the HP 3850 and HP 2210, 38 and 

34 steps, respectively, were required to 

maintain data confidentiality and network 

security. 

 Once the data reached the NC FO, an 

interface was developed to handle incoming 

files, view the transmitted data, and track 

refusals and completed samples. See 

Appendix C. 

12. OBSERVATIONS AND 

 PERSPECTIVES 

This section details the perceptions and 

thoughts of the field enumerators and 

observations of staff from the NC FO, RDD 

and Census and Survey Division. 

12.1 FIELD ENUMERATORS

In February 2005, the 22 field 

enumerators were sent a feedback form to 

obtain their perspective on using PDAs for the 

COY research project. See Appendix D for a 

copy of the enumerator feedback form. 

Sixteen enumerators returned the feedback 

form with information. The remaining six 

enumerators were neutral with no suggestions 

to use or not. The results were as follow: 

 When asked if they would like to use 

iPAQs to record other types of survey data in 
9 

the future, it was an even split, 50 percent (8 

enumerators) indicated “yes” and the other 

half, “no”. Of those wanting to use the iPAQ 

again, only one had no prior computer 

experience. For those that preferred not to use 

the iPAQ, three enumerators did not have 

prior computer experience. When asked if 

they would want to use the iPAQ again 

specifically for COY, 14 did and 2 did not. 

Ten enumerators recorded the COY 

data onto the paper form, and later entered the 

data into the iPAQ just outside the field. Five 

enumerators entered the data directly into the 

iPAQ while in the field, and one entered the 

data at various locations. 

 The enumerators felt that there was a 

reduced number of calls from the field office 

concerning their work since the iPAQs’ edits 

showed any errors while they were collecting 

the data. The enumerators also liked not 

having to rush to Federal Express to mail the 

paper forms. 

However, there were four issues that 

the enumerators did not like about the iPAQs. 

First, the 34 to 38 steps necessary to encrypt 

and transmit the data seemed rather lengthy. 

Second, some enumerators had difficulty 

reading the iPAQ’s screen due to sun glare. 

Third, enumerators did not like finding errors 

in the program, despite the field office’s best 

efforts to provide a downloadable fix that day 

or the next. Finally, some enumerators were 

worried about protecting the iPAQ from the 

elements, like rain and dirt, and hence, wanted 

a more durable device. Four enumerators 

suggested that a belt clip/holster for the iPAQ 

might help in protecting the device from being 

dropped while removing/inserting the device 

from a pant/coat pocket. 

Only one enumerator stated that the 

iPAQ’s battery life was insufficient and 

suggested that a car charger should be 

provided. 

Enumerators did not express any 

concerns over the security of the iPAQ. They 

were confident that the security procedures 

would be sufficient. They did feel that the 

data were as secure, if not more, than a paper 

questionnaire.

Regarding future uses of the devices, 

seven enumerators indicated that they would 

like short questionnaires such as the Quarterly 

Agricultural Survey on the iPAQ for data 

collection. The authors acknowledge that a 

Quarterly Agricultural Survey’s questionnaire 

consists of 8 or more pages, making it a 

questionable candidate for an iPAQ 

application.

12.2 STAFF OBSERVATIONS 

 Staff from the NC FO, RDD, and the 

Census & Survey Division observed and/or 

worked with some of the field enumerators. 

In general the field enumerators appeared 

comfortable using the iPAQs. One 

enumerator commented that using the stylus 

was not much different than using paper and 

pencil. There were two distinct ways that the 

field enumerators used the iPAQs. The first 

way was by recording the data directly into 

the iPAQ. The second way was by entering 

the data onto the paper form first and then 

inputting the data into the iPAQ. Those that 

waited until the end felt that this way was 

faster for them. During one of the data 

collection observations, the iPAQ was 

accidentally dropped in the dirt, but luckily 

displayed no ill effects. Also, the data 

collection instrument would not allow Unit 2’s 

data to be entered before Unit 1. This caused 

the field enumerators to adhere to the proper 

data collection procedures. Although, they 

could have recorded Unit 2’s data on paper 

and then enter the data into the iPAQ, this idea 

wasn’t thought of. 
10 

13. FINDINGS 

Twenty-two enumerators successfully 

recorded the COY data into their iPAQs and 

transmitted the data to the NC FO. 

The use of automated edits allowed 

most errors to be caught during data 

collection. Historically, errors were caught 

when the field office reviewed the completed 

forms or after the data were keyed and 

processed through a mainframe computer edit. 

This led to trying to contact the enumerator 

via telephone to resolve the issue. If the 

enumerator couldn’t be contacted, the 

objective yield survey statistician had to make 

his/her best decision with the given 

information. 

Some examples of errors that were 

corrected before data transmission are 

recording Row 2 data into Row 1, recording 

Unit 2’s data before Unit 1, and entering the 

incorrect date or enumerator ID. Even for 

those enumerators who first recorded the data 

onto the paper form and later transferred the 

information into the iPAQ, many errors were 

caught and corrected.

Utilizing the iPAQs provided 

enumerators additional time to collect the 

data. In the past, the field enumerators had to 

reduce the data collection period by two days 

in order to allow for mailing the forms to the 

field office. This two-day window was 

needed for office staff to receive the forms via 

Federal Express, review the forms and correct 

any problems. By having the data transmitted 

the same day they were collected, the field 

office could review the data the same day or 

the next morning. This provided the field 

enumerators with an additional two days of 

data collection. 

 The need for keying completed forms 

in the field office was eliminated, since all 

data were electronically submitted from the 

field. 

There was only one problem involving 

hardware resulting in an iPAQ becoming 

inoperable. This occurred when an iPAQ got 

wet in the pocket of an enumerator’s rain 

jacket. This iPAQ did not have a rugged case 

which might have prevented it from being 

damaged. 

14. BENEFITS & COSTS 

 This section examines the benefits and 

costs of using PDAs for collecting Cotton 

Objective Yield Survey data. 

14.1 BENEFITS

Using personal digital assistants to 

collect COY data has several benefits. These 

include: 

● Reduced data collection errors, saving 

office staff and enumerators’ time and 

mileage to revisit sample plots. This 

resulted in an estimated $700 in 

savings. 

● Provided additional time for 

enumerators to collect the data. 

 

● Eliminated $3,500 in Federal Express 

costs in mailing completed forms to 

the office. This includes saved 

enumerator salary and mileage to ship 

the forms. 

● Eliminated office data entry. This 

resulted in an estimated $800 savings 

(salary and benefits). 

● Enabled preliminary data analysis to 

begin sooner since the statistician did 

not have to wait for the forms to be 
11 

received in the mail. 

● PDAs can be re-used for next year’s 

COY as well as other projects. The 

life span of the iPAQs utilized is 3-5 

years, according to Hewlett Packard’s 

Technical Support Center. This helps 

spread the initial hardware and 

software costs over time. 

14.2 COSTS 

The total cost for the project was 

$26,550. Hardware and software accounted 

for $5,850. Not included in these figures is 

the cost ($6,000) of the ten iPAQs which were 

acquired for another project. 

No additional costs were incurred for 

the enumerator training workshop since the 

iPAQ training was incorporated into the 

overall COY workshop. However, three 

mini-training workshops were held a few days 

after the formal workshop to review the 

transmission process with enumerators. Each 

training session lasted an average of four 

hours. This additional training was necessary 

since the NASS Access Server wasn’t 

operational during the enumerator training 

workshop. Total cost for enumerator and 

Field Office staff salaries, benefits, and travel 

was estimated at $2,700. 

Salaries and benefits for the NC FO 

staff to research and develop the project, 

including developing the instrument and the 

data transmission/encryption process, creating 

instructions/handouts for the enumerators, 

training enumerators and answering calls from 

enumerators who had trouble using the iPAQs 

and/or transmitting the data, was 

approximately $18,000. 

Finally, one iPAQ, as noted earlier, 

was damaged and would need to be replaced 

for next year’s survey. 

Table 3 shows the breakdown of these 

costs. 

Table 3: iPAQ Project Costs 

Item Quantity Cost $ 

HP3850 10 0 

HP2210 8 3,200 

Modem 18 1,050 

Sentry 2020 18 700 

Scotty FTP 18 450 

Scotty FTP - Host 1 25 

Dot Pocket 1 25 

Rugged Cases 

(HP3850) 8 400 

Training 

(Transmission) 2,700 

Office Staff 

(Salary and Benefits) 18,000 

Total 26,550 

14.3 COST/BENEFIT CONCLUSION

It was difficult to conduct a precise 

cost/benefit analysis because of the subjective 

nature of many of the benefits and the 

inability to define the exact amount of cost 

savings. Putting a value on improved data 

collection procedures and the ability to 

analyze data more quickly is fairly subjective. 

Table 4 summarizes the estimated costs and 

savings in 2004. 
12 

Table 4: Estimated Costs versus Savings 

Item Cost $ Savings $ 

Hardware/Software 5,850 

Research and 

Development 18,000 

Training 2,700 

Federal Express 3,500

Sample Plot 

Revisits 700

Editing, Keying 800

Total 26,550 5,000

Enumerator cost per sample was $445 

when the iPAQ technology was introduced in 

2004. Comparing this cost with 2003’s costs 

per sample ($453), when paper forms were 

used, shows that the savings per sample is 

trivial. 

Hence, for the PDA project there was a 

$21,500 short-fall ($5,000 minus $26,500) in 

using the iPAQs. 

Before this report was published the 

NC FO conducted the 2005 COY, the 

following looks at a five year cycle 

incorporating the additional cost information 

obtained in 2005. 

 The $18,000 in staff resources to 

research and develop the COY iPAQ program 

in 2004 was reduced to approximately $3,000 

to maintain and improve the technology in 

2005. 

The total cost in year 1 was $26,550. 

The total cost for year 2 was $3,500. The 

projected costs in years 3-5 are estimated at 

$3,500 per year. (Three thousand dollars for 

office staff salaries and benefits to 

manage/maintain the data collection 

instrument and $500 for one replacement 

iPAQ per year.) Thus, the projected total outof-pocket expenses for the first five years are 

estimated at $40,550. 

However, eliminating Federal Express 

shipments, reducing additional sample plot 

revisits, and eliminating manual editing and 

data entry costs saved $5,000 in the first year. 

This equates to a total of $25,000 in savings 

over five years. 

Hence, utilizing the iPAQ technology 

only for COY would cost an additional 

$15,550 over five years compared with the 

standard way of collecting data using the 

paper questionnaire only. 

Note: In 2005, the cost per sample 

was $352. Compared with 2004’s cost per 

sample of $445, this is a $93 in savings per 

sample. The reasoning for these substantial 

savings is still under review but if some of 

these savings are attributed to the iPAQ, then 

these additional savings will negate some of 

the $15,550 deficit. 

15. LESSONS LEARNED 

Data transmission speed was not a 

problem, but the number of steps required for 

transmission was cumbersome. A majority of 

the steps were associated with encrypting the 

data before transmission and authentication to 

the NASS Access Server. A future goal is to 

streamline the encryption/transmission 

process. This goal is more obtainable as 

NASS moves away from the NASS Access 

Server to a virtual private network. Problems 

were also encountered with enumerators 

incorrectly entering their passwords. 

A PDA case that could be clipped on a 

belt would help the enumerators with 

accessing the PDA to record counts. This 

would provide a significant advantage over 

taking it in and out of a pocket. 

If further expansion of PDA usage to 

other FOs is to occur, a back-up to the NASS 

Access Server is needed. Since the server was 

down during training, a live example of data 

transmission could not be shown, however, 

the NC FO had developed a hard-copy of the 
13 

transmission instructions. 

16. FUTURE OF PDAS FOR DATA 

COLLECTION IN NASS 

The future of PDAs for data 

collection within NASS needs additional 

investigation. Applications, like field 

enumerator timesheets, are currently being 

investigated by the NC FO. As more uses 

for PDAs are found, the benefit to cost ratio 

will improve, thereby opening the possibility 

of expanding the use of PDAs to additional 

field offices. 

17. REFERENCES 

Eklund, Bruce 1991, “Mobile 

 Computerized Data Entry for the 

 Livestock Prices Received Survey”, 

 SRB 91-10, United States Department 

 of Agriculture, National Agricultural 

 Statistics Service. 

Eklund, Bruce 1993, “Computer Assisted 

 Personal Interviews: Experience and 

 Strategy”, STB-93-01, United States 

 Department of Agriculture, National 

 Agricultural Statistics Service. 

Eklund, Bruce 1994, “Computer Assisted 

 Personal Interviewing, Office Data 

 Processing, and the June Agricultural 

 Survey”, STB-94-01, United States 

 Department of Agriculture, National 

 Agricultural Statistics Service. 

Gerling, Michael 2004, “A New Look 

 into Portable Electronic Devices for 

 Field Data Collection in the National 

 Agricultural Statistics Service”, White 

 Paper-05-01, United States Department 

 of Agriculture, National Agricultural 

 Statistics Service. 

 
14 

Appendix A 

Cotton Objective Yield Survey – Form B 
15 
16 
17 

Appendix B 

Transmission Instructions For The HP 3850 
18 
19 
20 
21 
22 
23 
24 

Appendix C 

Screen Shots of the Data Administrative Program 
25 

Screenshot of the data interface used to view the transmitted data. This was 

useful for editing and/or printing hard copies of the data. 
26 

Screenshot of the Sample Status Screen used in tracking refusals, missing and 

completed samples. By being able to query collection months, this served as a 

comprehensive reference for sample status. Data for the selected sample and month 

could be viewed by double clicking on the sample of interest 
27 

Appendix D

Enumerator Feedback Form
28 

Evaluation of the IPAQ 

For Data Collection 

February 14, 2005 

1. Would you like to use the IPAQ for the next Cotton Objective Yield in the field 

to record counts? Why or why not? 

2. Would you like to use the IPAQ for the next Cotton Objective Yield in some 

capacity? How would you use it? 

3. What other field data collection surveys could the IPAQ be used for? 

4. Explain how you (and your partner) recorded counts into the IPAQ (i.e. at 

home, at edge of field, in the field, etc). Looking back, would you have 

changed how you recorded the data? 

5. From your perspective, what we some of the benefits of using the IPAQ? 
29 

6. From your perspective, what we some of the obstacles you encountered? 

And your suggestion on any correction to them that we could make for 

2005. 

 

7. Have you used a computer (any type) before? 

_____ Yes _____ No 

8. How would you rate the ease of use of the IPAQ in the field? 

___ very easy ____ easy _____ difficult _____ very difficult 

9. How would you rate the overall ease of use of the IPAQ? 

___ very easy ____ easy _____ difficult _____ very difficult 

10. Please comment on each of the following areas: 

 Durability of PDA (drops, rain, dust, mud) 

 Battery Life 

 Data Transmission 

 Security of the IPAQ 

 Training 

 Instructions/Hand-Outs 
30 

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General comments: 

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Enumerator Name/Date: ___________________________________________