# Presentation: 016722

## USCENSUSBUREAU

*Helping You Make Informed Decisions*

## American Community SurveyIncome

- Data Collection, Processing, and Comparisons to the 1990 Census
- Kirby G. Posey
- Edward J. Welniak

## What is the American Community Survey?

- A new survey designed to eventually replace the census long form.
- A way to provide the data communities need every year instead of once every ten years.

## 1996 American Community Survey (ACS) Test Sites and Population

- Brevard County, Florida 		447,597
- Fulton County, Pennsylvania	  14,358
- Multnomah County, Oregon	613,144
- Rockland County, New York	270,962

## 1996 ACS Income Sources

- Wage / Salary
- Self-Employment
- Interest, dividends, net rental income
- Social Security
- Retirement
- SSI, AFDC, or other public assistance
- Other sources of income

## 1990 Census Income Sources

- Wage / Salary
- Self-Employment from non-farm business
- Farm self-employment
- Interest, dividends, net rental income
- Social Security
- SSI, AFDC, or other public assistance
- Retirement
- Other sources of income

## Mode of Data Collection for 1996 ACS

- Primarily Self-Enumeration / Mail Out - Mail Back
- Computer Assisted Telephone Interviewing (CATI) for non-response
- Computer Assisted Personal Interviewing (CAPI) for non-response

## Reference Period: The Most Important Difference Between the 1996 ACS and the 1990 Census

- The ‘90 Census asked respondents to report their income for the LAST CALENDAR YEAR

- The 1996 ACS asked respondents to report their income for the PAST 12 MONTHS

## The Split Panel Test	

- We conducted a Split Panel Test of about 19,000 households with a 49-percent response rate to evaluate the impact of the reference period change.
- Half the questionnaires in the Split Panel Test asked respondents to report income during the last 12 months.  The other half asked respondents to report income during the past calendar year.

## ACS Split Panel Results-Results of the Wage and Salary Question by Different Reference Periods

**Note:  This difference was statistically significant.**

## ACS Split Panel Results -Results of the Self-Employment Question by Different Reference Periods 

**Note: This difference was statistically significant.**

## Summary of the Split Panel Results

- Wages and Salary income was lower for the “past 12 months” reference period.
- Self-Employment income was higher for the “past 12 months” reference period.
- There were no statistically significant differences in all other sources of income between the two reference periods.

## Proportion of persons responding to each income item by reference period

## Response rates are slightly better for “Past 12 Months” reference period

- There was a statistically significant increase in the response rate for public assistance income asked for the “past 12 months” reference period compared to the “last calendar year” reference period.
- All other income items appeared to have higher response rates for the “past 12 months” reference period although none were statistically significant.

## Adjustment factors allowed the presentation of all reference periods in terms of constant 1996 dollars

- We used monthly Consumer Price Indices (CPIs) from the Bureau of Labor Statistics to present all reference periods in terms of adjusted 1996 dollars.
- Our adjustment factors were calculated by summing the 12 monthly CPIs for 1996 and dividing by the sum of the 12 monthly CPIs that made up the respondent’s reference period.

## Rolling Reference Periods and their Adjustment Factors

-                                                         (--------------------------------------) January        1.000000
-                                                    (--------------------------------------)      December    1.002717
-                                               (--------------------------------------)           November   1.005395
-                                          (--------------------------------------)                October       1.007871
-                                     (--------------------------------------)                     September   1.010360
-                                 (--------------------------------------)                         August        1.012752
-                             (--------------------------------------)                             July             1.015210
-                         (--------------------------------------)                                 June            1.017515
-                    (--------------------------------------)                                      May            1.019941
-               (--------------------------------------)                                           April           1.022379
-          (--------------------------------------)                                                March         1.024773
-      (--------------------------------------)                                                    February     1.027009
-  (--------------------------------------)                                                        January       1.029312
-  J  F  M  A  M  J  J  A  S  O  N  D | J  F  M  A  M  J  J  A  S  O  N  D | J
- |<--------------1995-------------->|<---------------1996------------->|

## 1996 ACS Edit Procedures

- _Edits_ - Basically the same process that was employed in the 1990 Census (and will be employed in the 2000 Census)
- _Missing Data_ - Adjusted allocation process slightly for a smaller sample size to help insure a demographic match between a respondent who did not report income and one who did

## Median Household IncomeComparisons in the ACS to Census and Small Area Income and Poverty Estimates (SAIPE)

## Summary

- We were concerned about the lower wage entries for the “past 12 month” reference period in comparison to the “last calendar year” as evidenced by the Split Panel Test.
- We were also concerned about the lower median household income in the ACS sites compared to the 1990 Census medians (adjusted for inflation).
- We took action by re-wording the income instructions on the ACS questionnaire stressing even more strongly the “past TWLEVE month” reference period.

## This paper can be downloaded at:

- www.census.gov/acs/www/index_b.htm
- then
- Click on “ACS Library”