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Highlights

(The numbers in parentheses denote the 90-percent confidence intervals.)

x About 20.2 (±1.3) million persons participated in a major assistance program on a long-term

basis; i.e., all 24 months of 1991 and 1992, constituting 8.3 (±0.5) percent of the population.

x The median length of time of receiving benefits from major means-tested assistance programs

was 7.9 months during the 1991-to-1993 period, the same as during the 1990-to-1992 period.

x Total median monthly family benefits from Aid to Families With Dependent Children (AFDC),

General Assistance, Supplemental Security Income (SSI), and food stamps were about $436

(±5.8) in 1992.

Acknowledgments

This report was prepared under the general direction of Kathleen S. Short, Chief, Poverty and

Wealth Statistics Branch. The tables for this report were programmed and prepared by Caroline

Carbaugh under the general direction of Angela M. Feldman-Harkins, Chief, Computer Programming and Applications Staff. Statistical assistance was provided by Bernadette D. Proctor and

Jean E. Tash. Overall direction was provided by Charles T. Nelson, Assistant Division Chief

(Economic Characteristics), Housing and Household Economic Statistics Division. Peer reviews

were provided by Timothy S. Grall, and Wilfred T. Masumura (Housing and Household Economic

Statistics Division).

Survey design and data operations were coordinated by Enrique J. Lamas, Chief, Income

Surveys Branch, Demographic Surveys Division. Data processing activities were directed by

Donna Riccini, Chief, Income Surveys Programming Branch, Demographic Surveys Division.

Data collection was conducted by the Bureau of the Census interviewers under the overall

direction of Field Division.

Sampling, estimation and statistical review were conducted by Vicki Huggins, Chief, Survey of

Income and Program Participation Branch, and Elaine C. Hock, Demographic Statistical Methods

Division.

The staff of Administrative and Publications Services Division, Walter C. Odom, Chief,

performed publication planning, design, composition, editorial review, and printing planning and

procurement. Margaret A. Smith provided publication coordination and editing.







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&(  %( $#HOUSING AND HOUSEHOLD

ECONOMIC STATISTICS DIVISION

Daniel H. Weinberg, Chief

SUGGESTED CITATION

Shea, Martina, Dynamics of Economic Well-Being: Program Participation, 1991 to 1993

U.S. Bureau of the Census. Current Population Reports, P70-46

U.S. Government Printing Office, Washington, DC, 1995.

For sale by Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.

BUREAU OF THE CENSUS

Martha Farnsworth Riche, Director

Bryant Benton, Deputy Director

Paula J. Schneider, Principal Associate

Director for Programs

Nancy M. Gordon, Associate Director

for Demographic Programs

ECONOMICS

AND STATISTICS

ADMINISTRATION

Economics and Statistics

Administration

Everett M. Ehrlich, Under Secretary

for Economic Affairs
Page

TEXT

Introduction......................................................................................... 1

Highlights ........................................................................................... 1

Program Participation Status in the United States: 1991 to 1993............................. 2

Race and Hispanic Origin....................................................................... 2

Age ............................................................................................... 5

Employment Status.............................................................................. 5

Disability Status ................................................................................. 8

Family Status .................................................................................... 8

TEXT TABLES

A. Receipt of Public Assistance by Race and Hispanic Origin ............................. 3

B. Receipt of Public Assistance by Age ..................................................... 6

C. Receipt of Public Assistance by Employment and Disability Status .................... 7

D. Receipt of Public Assistance by Family Status........................................... 10

FIGURES

1. Rates of Participation in Major Means-Tested Programs: 1991 and 1992 ............. 2

2. Median Durations of Major Means-Tested Program Spells by Various

Characteristics: 1991 to 1993 ............................................................ 4

3. Distribution of Spells of Participation in Major Means-Tested Programs by Spell

Length: 1991 to 1993 ................................................................... 4

4. Median Durations of Program Spells: 1991 to 1993.................................... 4

5. Median Benefits From Major Means-Tested Assistance Programs by Various

Characteristics: 1992.................................................................... 8

APPENDIXES

A. Definitions and Explanations............................................................... A–1

B. Source and Accuracy Statement .......................................................... B–1

APPENDIX TABLES

B–1. SIPP Generalized Variance Parameters for Estimates From the 1990 Longitudinal

File......................................................................................... B–4

B–2. SIPP Generalized Variance Parameters for Estimates From the 1991 Longitudinal

File......................................................................................... B–4

B–3. SIPP Indirect Generalized Variance Parameters for Annual Estimates Based on

Monthly Averages From the 1990 Cross-Sectional Files............................... B–4

B–4. SIPP Indirect Generalized Variance Parameters for Annual Estimates Based on

Monthly Averages From the 1991 Panel Cross-Sectional Files........................ B–4

iii

Contents
B–5. Standard Errors of Median Monthly Family Benefits in the 1991 SIPP Panel by

Selected Characteristics.................................................................. B–5

B–6. Standard Errors of Median Spell Duration for Persons Experiencing Spells in the

1991 SIPP Panel by Selected Characteristics .......................................... B–5

B–7. Bases for Estimates........................................................................ B–6

iv
Dynamics of Economic Well-Being:

Program Participation, 1991 to 1993

Note: All demographic surveys, including the Survey of Income and Program Participation (SIPP), are affected by

undercoverage of the population. This undercoverage results from missed housing units and missed persons within sample

households. Compared to the level of the 1980 decennial census, overall undercoverage in SIPP is about 7 percent.

Undercoverage varies with age, sex, and race. For some groups, such as 20 to 24 year old Black males, the undercoverage

is as high as 27 percent compared to the census. It is important to note that the survey undercoverage is an addition to the

decennial census undercoverage, which in 1980 was estimated to be about 1 percent overall and about 8.5 percent for

Black males. The weighting procedures used by the Census Bureau partially correct for the bias due to undercoverage.

However, its final impact on estimates is unknown.

INTRODUCTION

This report uses data from the SIPP to examine the

participation in government assistance programs at a point

in time and over a 32-month period. It presents data from

the complete panel file of the 1991 SIPP which covers the

time period from October 1990 through August 1993.

SIPP enables comparisons of rates of program participation and the amounts of benefits received among persons of different demographic and socioeconomic characteristics. It also can be used to study the distribution of spell

durations. The panel file contains monthly information on

the program participation status of individuals as well as on

many other characteristics which can vary over the panel,

such as family and labor force status. Efforts were made

during the life of the panel to follow persons who moved to

ensure that the sample remained representative of the

noninstitutional population of the United States.

It should be noted that some longitudinal estimates

presented here are based on persons who either were

interviewed in all waves of the reference period or for

whom imputed wave information exists.1 Insofar as persons with missing actual or imputed wave information

differed in their experience of program participation from

those who did not, these longitudinal estimates may be

biased.

HIGHLIGHTS

(The numbers in parentheses denote the 90-percent

confidence intervals.)

x About 20.2 (±1.3) million persons participated in a major

assistance program on a long-term basis; i.e., all 24

months of 1991 and 1992, constituting 8.3 (±0.5) percent

of the population.

x The median length of time of receiving benefits from

major means-tested assistance programs was 7.9 months

during the 1991-to-1993 period, the same as during the

1990-to-1992 period.

x Total median monthly family benefits from Aid to Families With Dependent Children (AFDC), General Assistance, Supplemental Security Income (SSI), and food

stamps were about $436 (±5.8) in 1992.

x About 5.8 (±0.5) percent of White persons participated

long-term in major assistance programs, compared to

18.9 (±2.5) percent of persons of Hispanic origin (who

may be of any race) and 24.2 (±1.4) percent of Black

persons. Most long-term participants in means-tested

assistance programs were White, 57.9 (±3.2) percent,

versus 36.2 (±2.6) percent who were Black and 20.9

(±2.7) percent who were Hispanic.

x Children were more likely to be long-term participants in

major assistance programs than elderly persons and

nonelderly adults, 13.4 (±1.2) percent versus 11.1 (±1.6)

and 5.6 (±0.5) percent.

x Unemployed workers and those out of the labor force,

although not significantly different from one another, had

substantially higher long-term participation rates in major

assistance programs than persons employed either full

or part time.

x The presence of a work disability increased the likelihood of long-term participation in major assistance programs from 3.8 (±0.5) to 18.3 (±2.3) percent.

x Persons in female-householder families were 22 times

as likely as persons in married-couple families to have

received AFDC or General Assistance and 13 times as

likely to have received food stamps on a long-term basis.

1

A ‘‘missing wave imputation’’ procedure was used for persons who

missed an interview but had completed interviews before and after the

missing wave.

1
PROGRAM PARTICIPATION STATUS IN THE

UNITED STATES: 1991 TO 1993

The tables in this report show data for persons rather

than for families or households. Persons are considered

participants in AFDC, General Assistance, or in the Food

Stamp Program if they are the primary recipient or if they

are covered under another person’s allotment. Persons are

counted as participants in a major means-tested assistance program if they live in public housing or are beneficiaries of one of the following programs: AFDC, General

Assistance, SSI, Medicaid, food stamps, and Federal or

State rent assistance. Benefit amounts from major meanstested assistance programs include AFDC, General Assistance, SSI, and food stamp benefits. For meaningful comparison of benefits, they are valued in constant 1992

dollars.

We consider four aspects of program participation:

1. The length of participation in various programs.

2. Long-term participation; i.e., the number and percent

of persons who participated each month of 1991 and

1992.

3. The number and percent of persons who participated

in various programs in an average month of 1991

(1992).

4. The number and percent of persons who participated 1

month or more during 1991 (1992).

Time spent in programs is an important dimension of

program participation. Some individuals have longer spells

than others, and policy approaches to provide short-term

relief are likely to differ from those intended to remedy

long-term dependency. SIPP allows longitudinal analysis

of program participation. It allows one to calculate median

spell durations as well as distributions of spells by spell

length, using survival analysis.

A substantial number of persons, 20.2 million, participated all 24 months of 1991 and 1992 in major meanstested programs. These long-term participants represented

8.3 percent of the population, a substantially higher proportion than the 7.6 percent in the previous 2-year period

(1990-1991). Approximately 34.0 million persons participated in a major means-tested assistance program in an

average month during 1992, representing 13.4 percent of

the population. The number of persons who ever participated during a single calendar year, 1992, was significantly

higher, 42.5 million (17.0 percent of the population), demonstrating substantial mobility (see table A and figure 1).

Table A shows that 2.8 percent of the population (almost

7 million) participated the entire 1991-1992 period in AFDC

or General Assistance, compared to 2.4 percent during the

1990-1991 period. About 4.3 percent of the population

(10.4 million persons) were long-term participants in the

Food Stamp Program, significantly higher than the 3.8

percent in the previous 2-year period.

The median spell duration of major means-tested assistance programs was 7.9 months during the 1991-to-1993

period, the same as during the 1990-to-1992 period. This

means that half of all spells lasted less than 7.9 months

and half lasted longer (figure 2). While 34.0 percent of

spells lasted between 1 and 4 months, smaller proportions

of spells fell in subsequent length categories: 16.0 percent

lasted between 5 and 8 months, and 7.0 percent between

9 and 12 months. However, 30.0 percent of all spells lasted

longer than 2 years (figure 3). As can be seen in figure 4,

the median length of time receiving AFDC or General

Assistance was 7.4 months during 1991 to 1993, significantly shorter than food stamp spells (9.6 months).

Table A shows that the median benefit amount received

in 1992 was $436 from one or more major means-tested

assistance programs, $363 from AFDC/General Assistance, and $206 from food stamps.

Race and Hispanic origin2. There was a strong association between race and Hispanic origin and the likelihood of

receiving means-tested assistance. Whites had significantly lower participation rates than Blacks, and persons of

Hispanic origin had rates intermediate between Whites and

Blacks. One-fourth (24.2 percent) of all Blacks received

assistance from a means-tested program during all 24

months of 1991 and 1992. The comparable figures for

Whites and persons of Hispanic origin were 5.8 percent

and 18.9 percent, respectively.

2

Persons of Hispanic origin may be of any race. The information on the

Hispanic population shown in this report was collected in the 50 States

and the District of Columbia, and therefore, does not include residents of

Puerto Rico.

Figure 1.

Rates of Participation in Major Means-Tested

Programs: 1991 and 1992

(Percent)

Participated

1 or more months

in 1991

Participated

1 or more months

in 1992

Participated

in an average

month

of 1991

Participated

in an average

month of 1992

Participated

all months of

1991 and

1992

16.4

17.0

12.7 13.4

8.3

2
Table A. Receipt of Public Assistance by Race and Hispanic Origin

Race and Hispanic origin

Average monthly participation

(thousands)

Persons ever participating

(thousands)

Persons participating all 24 months

(thousands)

Med

du

(m

Calendar year

1991

Calendar year

1992

Calendar year

1991

Calendar year

1992

Calendar years

1991 and 1992

(91 panel)

Calendar years

1990 and 1991

(90 panel)

9

pane

Number Percent Number Percent Number Percent Number Percent Number Percent Number Percent 

ALL PROGRAMS1

Total . . . . . . . . . . . . . . . . 31 695 12.7 33 954 13.4 40 606 16.4 42 470 17.0 20 244 8.3 18 093 7.6 7.

White . . . . . . . . . . . . . . . . . . . . . 19 875 9.5 21 690 10.3 26 319 12.8 28 256 13.6 11 731 5.8 9 894 5.0 7.Black. . . . . . . . . . . . . . . . . . . . . . 10 126 32.5 10 507 33.0 12 162 39.4 12 135 38.8 7 323 24.2 7 172 24.6 12.

Hispanic origin2. . . . . . . . . . . . . 5 743 26.4 6 410 26.9 7 980 34.9 8 348 34.2 4 225 18.9 3 323 17.7 7.

AFDC OR GENERALASSISTANCE

Total . . . . . . . . . . . . . . . . 11 869 4.7 11 862 4.7 15 714 6.4 15 111 6.0 6 777 2.8 5 634 2.4 7.

White . . . . . . . . . . . . . . . . . . . . . 6 484 3.1 6 379 3.0 8 839 4.3 8 482 4.1 3 184 1.6 2 545 1.3 6.Black. . . . . . . . . . . . . . . . . . . . . . 4 560 14.6 4 723 14.8 5 819 18.8 5 736 18.4 3 008 10.0 2 497 8.6 11.

Hispanic origin2. . . . . . . . . . . . . 2 351 10.8 2 439 10.2 3 287 14.4 3 258 13.3 1 463 6.5 1 066 5.7 11.

FOOD STAMPS

Total . . . . . . . . . . . . . . . . 19 383 7.8 20 700 8.2 25 837 10.5 27 113 10.8 10 402 4.3 9 102 3.8 9.

White . . . . . . . . . . . . . . . . . . . . . 11 435 5.5 12 583 6.0 15 770 7.7 17 231 8.3 5 829 2.9 4 707 2.4 7.Black. . . . . . . . . . . . . . . . . . . . . . 6 901 22.1 7 072 22.2 8 716 28.2 8 605 27.5 4 021 13.3 3 823 13.1 14.

Hispanic origin2. . . . . . . . . . . . . 3 770 17.3 4 222 17.7 5 309 23.2 5 859 24.0 2 299 10.3 1 724 9.2 14.

1All programs include AFDC, General Assistance, SSI, food stamps, Medicaid, and housing assistance. Median monthly benefits from all programs include 

Assistance, SSI, and Food Stamp programs only.

2Persons of Hispanic origin may be of any race.
Figure 2.

Median Durations of Major Means-Tested Program

Spells by Various Characteristics: 1991 to 1993

All persons

White

Black

Hispanic origin1

Under 18 years

Employed full time

Employed part time

Unemployed

7.9

7.6

12.3

7.9

7.8

7.8

6.4

7.7

7.0

15.0

1 Persons of Hispanic origin may be of any race.

18 to 64 years

Not in labor force

With a work disability

With no work disability

Persons in marriedcouple families

Persons in femalehouseholder families

Unrelated individuals

14.1

7.4

7.3

14.9

10.8

(Months)

Figure 3.

Distribution of Spells of Participation in Major

Means-Tested Programs by Spell Length:

1991 to 1993

(Percent)

1–4 5–8 9–12 13–16 17–20 21–24 > 24

34

16

7

5

30

4 4

Months

Figure 4.

Median Durations of Program Spells: 1991 to 1993

(Months)

7.9

7.4

9.6

Major assistance

programs

AFDC or General

Assistance

Food stamps

4
Whites experienced an increased probability of longterm participation in means-tested programs combined,

and in food stamps, compared to the previous time period.

Their participation in means-tested programs increased

from 5.0 percent for the 1990-1991 period to 5.8 percent for

the 1991-1992 period. The corresponding increase in food

stamp participation was from 2.4 to 2.9 percent. Blacks

experienced a higher likelihood of long-term AFDC/General

Assistance participation in the latter 2-year period, 10.0

percent compared to 8.6 percent, but no higher overall

participation probability.

Lengths of participation differed significantly between

Whites and Blacks (see table A). Whites received AFDC/

General Assistance, food stamps, and major combined

benefits for shorter periods than Blacks. For instance, a

median AFDC/General Assistance spell lasted 6.6 months

for Whites, compared to 11.8 months for Blacks. There

were no consistent significant differences in the median

time of participation between Whites and persons of Hispanic origin on one hand, and between Blacks and persons

of Hispanic origin on the other hand.

Persons of Hispanic origin had shorter spells of major

assistance and AFDC/General Assistance during the 1991-

to-1993 period than during the 1990-to-1992 period. Table

A shows that their median AFDC/General Assistance spell

duration fell from 15.3 months in the 1990 panel to 11.7

months in the 1991 panel. Similarly, the median duration of

major assistance spells fell from 10.2 to 7.9 months.

The median of the sum of means-tested family benefits

was higher for Black participants than for their White

counterparts. Whites received median benefits of $399 in

1992, compared to $484 for Blacks. Persons of Hispanic

origin had median benefits of $478, not significantly different from Blacks. Similar differences by race and ethnicity

existed for food stamp benefits. In contrast, the median

benefits from AFDC/General Assistance received by Black

participants were substantially lower than those received

by their White and Hispanic origin counterparts. Whites

and Hispanic origin persons received equal AFDC/General

Assistance benefits.

The disparity between Whites, Blacks, and persons of

Hispanic origin in the likelihood of receiving benefits and

the amount of means-tested assistance they received

result from differences in poverty status and its correlates,

such as family type. Blacks were almost three times as

likely as Whites to be poor in an average month of 1992,

and persons of Hispanic origin had a similar rate to Blacks.

Blacks, however, were significantly more likely than persons of Hispanic origin to be poor all 24 months of 1991

and 1992, 15.7 versus 11.8 percent.3 While 10.4 percent of

Whites lived in female-householder families without a

spouse present in 1992, 38.6 percent of Blacks and 18.5

percent of persons of Hispanic origin did so.4

Despite significantly higher participation rates for Blacks

and persons of Hispanic origin, most participants were

White. Of those who participated in a major assistance

program all 24 months of 1991 and 1992, 57.9 percent

were White, 36.2 percent were Black, and 20.9 percent

were of Hispanic origin.

Age. Children had higher rates of participation in major

means-tested assistance programs than persons in other

age groups, reflecting their higher likelihood of living in

poverty. As shown in table B, 13.4 percent of all children

participated all 24 months of 1991 and 1992 in meanstested assistance programs, while only 5.6 percent of

nonelderly adults and 11.1 percent of the elderly did so.

Children were also more likely than other age groups to

receive AFDC/General Assistance and food stamps on a

long-term basis.5

Table B shows that the median food stamp spell for

children was 11.9 months, significantly longer than the 7.6

months for nonelderly adults. Children had a median

AFDC/General Assistance spell of 7.8 months, significantly

shorter than the 12.5 months in previously published data

based on the 1990-to-1993 period.

Median monthly family benefits were substantially higher

for children than for nonelderly adults, and were higher for

nonelderly adults than for the elderly. While children received

median benefits from means-tested programs in the amount

of $531 in 1992, nonelderly adults and the elderly received

$417 and $198, respectively (table B).

Employment status. Table C shows data on the relationship between the employment status of persons 18 years

and older and their participation in means-tested programs.

The probability of long-term participation in major meanstested programs was highest for the unemployed (16.7

percent) and those out of the labor force (15.0 percent),

followed by those employed part time (3.7 percent), and

full-time workers (1.3 percent). (The percentages for the

unemployed and those out of the labor force were not

significantly different).

The relationship between employment status and the

degree to which assistance is received reflects differences

in income. The unemployed had the highest average

monthly poverty rate in 1992, 37.8 percent, followed by

persons not in the labor force (19.2 percent), those employed

part time (12.6 percent), and those employed full time (3.5

percent).3

3

U.S. Bureau of the Census, Current Population Reports, Series P-70,

No. 45, Dynamics of Economic Well-Being: Poverty, 1991 to 1993

forthcoming.

4

U.S. Bureau of the Census, Current Population Reports, Series P-60,

No. 185, Poverty in the United States: 1992, U.S. Government Printing

Office, Washington, DC, 1993. 5

There was no significant difference between elderly and nonelderly

adults in the likelihood of receiving food stamps on a long-term basis.

5
Table B. Receipt of Public Assistance by Age

Age

Average monthly participation

(thousands)

Persons ever participating

(thousands)

Persons participating all 24 months

(thousands)

Medi

du

(mo

Calendar year

1991

Calendar year

1992

Calendar year

1991

Calendar year

1992

Calendar years

1991 and 1992

(91 panel)

Calendar years

1990 and 1991

(90 panel)

91

pane

Number Percent Number Percent Number Percent Number Percent Number Percent Number Percent 

ALL PROGRAMS1

Total. . . . . . . . . . . . . . . . 31 695 12.7 33 954 13.4 40 606 16.4 42 470 17.0 20 244 8.3 18 093 7.6 7.9 

Under 18 years. . . . . . . . . . . . . 13 991 21.2 15 222 22.5 18 104 27.1 18 833 27.8 8 993 13.4 7 817 12.2 7.8 18 to 64 years . . . . . . . . . . . . . 13 813 9.0 14 751 9.5 18 369 12.1 19 409 12.6 8 315 5.6 7 761 5.3 7.8 

65 years and over . . . . . . . . . . 3 890 12.8 3 982 13.0 4 133 14.5 4 229 14.6 2 937 11.1 2 515 9.6 (X

AFDC OR GENERALASSISTANCE

Total................ 11 869 4.7 11 862 4.7 15 714 6.4 15 111 6.0 6 777 2.8 5 634 2.4 7.4 

Under 18 years. . . . . . . . . . . . . 7 222 10.9 7 292 10.8 9 333 14.0 8 986 13.3 4 279 6.4 3 469 5.4 7.8 

18 to 64 years . . . . . . . . . . . . . 4 576 3.0 4 492 2.9 6 273 4.1 6 027 3.9 2 450 1.6 2 134 1.4 6.4 65 years and over . . . . . . . . . . 71 0.2 78 0.3 107 0.4 98 0.3 48 0.2 32 0.1 (BFOOD STAMPS

Total. . . . . . . . . . . . . . . . 19 383 7.8 20 700 8.2 25 837 10.5 27 113 10.8 10 402 4.3 9 102 3.8 9.6 

Under 18 years. . . . . . . . . . . . . 10 127 15.3 10 780 15.9 13 177 19.7 13 634 20.2 5 717 8.5 4 798 7.5 11.9 

18 to 64 years . . . . . . . . . . . . . 8 125 5.3 8 716 5.6 11 363 7.5 12 079 7.9 3 945 2.6 3 652 2.5 7.6 65 years and over . . . . . . . . . . 1 131 3.7 1 204 3.9 1 297 4.6 1 400 4.8 741 2.8 652 2.5 12.8 

X Not applicable. B The base for the derived figure is less than 200,000.1All programs include AFDC, General Assistance, SSI, food stamps, Medicaid, and housing assistance. Median monthly benefits from all programs include 

Assistance, SSI, and Food Stamp programs only.
Table C. Receipt of Public Assistance by Employment and Disability Status

Employment and disability

status

Average monthly participation

(thousands)

Persons ever participating

(thousands)

Persons participating all 24 months

(thousands)

M

Calendar year

1991

Calendar year

1992

Calendar year

1991

Calendar year

1992

Calendar years

1991 and 1992

(91 panel)

Calendar years

1990 and 1991

(90 panel)

pa

Number Percent Number Percent Number Percent Number Percent Number Percent Number Percent 

ALL PROGRAMS1

Employment and Labor

Force Status

(persons 18 years and over)

Employed full time. . . . . . . . . . . . . 3 119 3.3 3 103 3.3 5 497 5.8 5 249 5.6 1 218 1.3 1 191 1.3 Employed part time. . . . . . . . . . . . 1 656 7.6 1 855 8.4 2 479 11.3 2 819 12.4 810 3.7 677 3.3 

Unemployed . . . . . . . . . . . . . . . . . . 1 600 23.5 1 721 22.8 2 269 32.6 2 173 29.8 1 063 16.7 821 16.7 

Not in labor force. . . . . . . . . . . . . . 11 330 18.8 12 053 19.8 12 256 21.4 13 396 23.0 8 161 15.0 7 586 14.2 1Disability Status

(persons 15 to 69 years)

With a work disability . . . . . . . . . . 6 231 22.2 6 496 23.6 7 180 27.1 7 504 29.6 4 598 18.3 4 258 16.4 1

With no work disability . . . . . . . . 10 072 6.9 11 002 7.4 14 506 9.9 15 316 10.3 5 557 3.8 5 050 3.6 

AFDC OR GENERAL

ASSISTANCE

Employment and Labor

Force Status

(persons 18 years and over)

Employed full time. . . . . . . . . . . . . 347 0.4 287 0.3 888 0.9 738 0.8 45 0.0 46 0.0 Employed part time. . . . . . . . . . . . 302 1.4 345 1.6 669 3.0 564 2.5 72 0.3 103 0.5 Unemployed . . . . . . . . . . . . . . . . . . 712 10.5 670 8.9 1 021 14.7 1 021 14.0 442 7.0 286 5.8 

Not in labor force. . . . . . . . . . . . . . 3 285 5.4 3 267 5.4 3 802 6.6 3 802 6.5 1 940 3.6 1 731 3.2 

Disability Status

(persons 15 to 69 years)

With a work disability . . . . . . . . . . 1 666 5.9 1 508 5.5 2 355 8.9 1 912 7.5 745 3.0 660 2.5 With no work disability . . . . . . . . . 3 655 2.5 3 787 2.6 5 002 3.4 5 188 3.5 1 970 1.4 1 661 1.2 FOOD STAMPSEmployment and Labor

Force Status

(persons 18 years and over)

Employed full time. . . . . . . . . . . . . 1 204 1.3 1 180 1.2 2 531 2.7 2 509 2.7 326 0.3 298 0.3 Employed part time. . . . . . . . . . . . 909 4.2 1 014 4.6 1 431 6.5 1 658 7.3 323 1.5 234 1.1 Unemployed . . . . . . . . . . . . . . . . . . 1 165 17.1 1 277 16.9 1 790 25.7 1 725 23.6 655 10.3 465 9.4 

Not in labor force. . . . . . . . . . . . . . 5 979 9.9 6 449 10.6 6 908 12.1 7 586 13.0 3 381 6.2 3 307 6.2 1

Disability Status

(persons 15 to 69 years)

With a work disability . . . . . . . . . . 3 375 12.0 3 418 12.4 4 323 16.3 4 366 17.2 1 717 6.8 1 678 6.5 

With no work disability . . . . . . . . . 6 101 4.2 6 818 4.6 8 865 6.1 9 808 6.6 2 922 2.0 2 497 1.8 

1All programs include AFDC, General Assistance, SSI, food stamps, Medicaid, and housing assistance. Median monthly benefits from all programs include 

Assistance, SSI, and Food Stamp programs only. 
Persons who were not in the labor force had longer

major assistance and food stamp spells than any of the

groups in the labor force. For instance, table C shows that

the median duration of major assistance spells was 15.0

months for persons out of the work force, 7.0 months for

the unemployed, 7.7 months for part-time workers and 6.4

months for full-time workers. Median food stamp spells

followed the same pattern.6

In 1992, the median sums of benefits from means-tested

programs for unemployed workers and persons out of the

labor force, while not statistically different from each other,

were higher than for those holding full- or part-time jobs. As

table C shows, unemployed workers received more generous food stamp benefits than full- and part-time workers

and persons out of the labor force.7

Disability status. The presence of a work disability in

persons 15 to 69 years of age increased the participation

rates in major means-tested programs. While 3.8 percent

of persons without a disability received assistance from

one or more programs in all months of 1991 and 1992, 18.3

percent of those with a disability did so (table C).

Again, the relative participation rates reflect differential

propensities of being poor. Persons with a work disability

were much more likely to be poor than persons with no

disability, 20.0 versus 9.9 percent in an average month of

1992.8

Median monthly family benefits from the Food Stamp

and AFDC/General Assistance programs were significantly

higher for persons without a work disability than for persons with a work disability, as can be seen in table C. In

1992, a work disability was associated with median monthly

family benefits of $130 for food stamp participants and

$307 for AFDC/General Assistance participants. Participants without a work disability received median benefits of

$211 and $366, respectively.

Family status. Participation in means-tested assistance

programs is higher for persons in female-householder

families than for persons in married-couple families and

unrelated individuals, as can be seen in table D. About 30.8

percent of persons in female-householder families participated all 24 months of 1991 and 1992, compared to 3.4

percent of persons in married-couple families and 10.0

percent of unrelated individuals. Furthermore, persons in

female-householder families were 22 times as likely as

6

There were no significant differences in median major assistance and

food stamp spell lengths between the three groups in the labor force. 7

There were no significant differences in median food stamp benefits

between full- and part-time workers on one hand, and between part-time

workers and those out of the labor force, on the other hand.

8

U.S. Bureau of the Census, Current Population Reports, Series P-70,

No. 45, Dynamics of Economic Well-Being: Poverty, 1991-1993, forthcoming.

Figure 5.

Median Benefits From Major Means-Tested Assistance

Programs by Various Characteristics: 1992

All persons

White

Black

Hispanic origin1

Under 18 years

Employed full time

Employed part time

Unemployed

436

399

484

478

531

417

198

224

260

403

18 to 64 years

Not in labor force

With a work disability

With no work disability

Persons in marriedcouple families

Persons in femalehouseholder families

Unrelated individuals

421

420

419

341

586

65 years and over

192

(Dollars)

8
persons in married-couple families to have received AFDC/

General Assistance on a long-term basis, and 13 times as

likely to have received food stamps.

Persons in female-householder families had longer median

spells than persons in married-couple families for major

programs taken together, and AFDC/General Assistance,

and food stamps separately. As can be seen in table D,

persons in married-couple families received AFDC/General

Assistance for 5.6 months, compared to 12.0 months for

persons in female-householder families. The shorter AFDC

stay of married-couple families is partly due to the transitory nature of unemployment (needy married-couple families must have an unemployed parent in order to receive

AFDC). Longer welfare spells generally reflect the inability

of female-householder families to exit poverty. As shown in

a companion report, persons in female-householder families have significantly longer poverty spells than persons in

married-couple households.9

Persons in female-householder families experienced an

increase in the spell duration of the major programs

combined, and the Food Stamp Program. For instance,

previously published data based on the 1990-to-1992

period showed median food stamp spell durations of 11.5

months, compared to 19.3 months during the 1991-to-1993

period.

Persons in married-couple families had significantly

higher AFDC/General Assistance and food stamp benefits

than persons in female-householder families, while the

opposite held true for benefits from major programs combined, as shown in table D. Median combined family

benefits for persons in female-householder families amounted

to $586 in 1992, which is substantially higher than the $341

received by their counterparts in married-couple families.

This suggests that female-householder families drew benefits from more programs or from a different mix of programs than married-couple families. Households composed entirely of recipients of AFDC are automatically

eligible for food stamps as long as they meet food stamp

employment-related requirements.10 Multiple program participation through ‘‘categorical’’ eligibility explains in part

the higher combined median benefits of female-householder

families compared to married-couple families. In addition,

not only was the poverty rate of persons in femalehouseholder families significantly higher than that of persons in married-couple families (37.5 versus 7.6 average

monthly percent in 1992),9 but persons in female-householder

families were also significantly more likely than persons in

married-couple families to have family incomes below

one-half of their respective poverty thresholds (19.8 versus

2.3 percent in 1992).11 Such low income levels make

multiple program participation and, therefore, higher combined benefits more likely.

9

U.S. Bureau of the Census, Current Population Reports, Series P-70,

No. 45, Dynamics of Economic Well-Being: Poverty, 1991-1993, forthcoming.

10U.S. Library of Congress. Congressional Research Service. Cash

and Noncash Benefits for Persons With Limited Income: Eligibility Rules,

Recipient and Expenditure Data, Fiscal Year 1986-88. Report for Congress No. 89-595 EPW, compiled by Vee Burke. Washington, DC, 1989.

86 p. 11U.S. Bureau of the Census, Current Population Reports, Series

P-60, No. 185, Poverty in the United States: 1992, U.S. Government

Printing Office, Washington, DC, 1993.

9
Table D. Receipt of Public Assistance by Family Status

Family status

Average monthly participation

(thousands)

Persons ever participating

(thousands)

Persons participating all 24 months

(thousands)

M

Calendar year

1991

Calendar year

1992

Calendar year

1991

Calendar year

1992

Calendar years

1991 and 1992

(91 panel)

Calendar years

1990 and 1991

(90 panel)

pa

Number Percent Number Percent Number Percent Number Percent Number Percent Number Percent 

ALL PROGRAMS1

Total. . . . . . . . . . . . . . . . . 31 695 12.7 33 954 13.4 40 606 16.4 42 470 17.0 20 244 8.3 18 093 7.6 

In families . . . . . . . . . . . . . . . . . . 26 721 12.5 29 063 13.4 34 852 16.4 36 899 17.1 16 910 8.1 15 108 7.4 

In married-couple families . . 11 436 6.7 12 895 7.5 17 033 10.0 18 862 10.9 5 821 3.4 5 533 3.3 In families with a female

householder, no spousepresent. . . . . . . . . . . . . . . . . . 14 232 40.1 15 068 40.7 16 467 46.9 16 762 46.0 10 547 30.8 9 154 29.0 1

Unrelated individuals . . . . . . . . . 4 973 13.6 4 891 13.5 5 754 16.5 5 571 16.3 3 334 10.0 2 985 9.3 1

AFDC OR GENERAL

ASSISTANCE

Total . . . . . . . . . . . . . . . . 11 869 4.7 11 862 4.7 15 714 6.4 15 111 6.0 6 777 2.8 5 634 2.4 

In families . . . . . . . . . . . . . . . . . . 11 544 5.4 11 590 5.3 15 156 7.1 14 677 6.8 6 692 3.2 5 530 2.7 

In married-couple families . . 3 001 1.8 3 012 1.7 4 664 2.7 4 881 2.8 1 160 0.7 1 041 0.6 In families with a female

householder, no spousepresent. . . . . . . . . . . . . . . . . . 8 257 23.2 8 287 22.4 10 028 28.5 9 485 26.0 5 380 15.7 4 414 14.0 1

Unrelated individuals . . . . . . . . . 325 0.9 272 0.8 558 1.6 434 1.3 85 0.3 104 0.3 FOOD STAMPS

Total . . . . . . . . . . . . . . . . 19 383 7.8 20 700 8.2 25 837 10.5 27 113 10.8 10 402 4.3 9 102 3.8 

In families . . . . . . . . . . . . . . . . . . 17 582 8.2 18 848 8.7 23 587 11.1 24 703 11.4 9 335 4.4 8 125 4.0 

In married-couple families . . 6 566 3.9 7 313 4.2 10 196 6.0 11 352 6.6 2 588 1.5 2 602 1.5 In families with a female

householder, no spousepresent . . . . . . . . . . . . . . . . . 10 474 29.5 10 968 29.7 12 629 35.9 12 643 34.7 6 556 19.2 5 424 17.2 1

Unrelated individuals . . . . . . . . . 1 801 4.9 1 853 5.1 2 250 6.5 2 409 7.1 1 067 3.2 977 3.0 1

1All programs include AFDC, General Assistance, SSI, food stamps, Medicaid, and housing assistance. Median monthly benefits from all programs include 

Assistance, SSI, and Food Stamp programs only.
Appendix A.

Definitions and Explanations

Population coverage. The estimates in this report are

restricted to the civilian noninstitutional resident population

of the United States and members of the Armed Forces

living off post or with their families on post.

Weights. Five sets of weights were used in this report.

Monthly weights for calendar years 1991 and 1992 were

used in deriving average monthly participation and monthly

family benefits for each year. Estimates of the number of

persons who participated all of 1991 and 1992 were based

on the 1991 panel weight. Calendar year weights for 1991

and 1992 were used to obtain estimates of the number of

persons who ever participated during a given year.

Reference periods for the characteristics age, employment status, family status, and participation in assistance programs. While employment status is observed

each wave, the other characteristics are observed each

month. In order to calculate average monthly statistics, the

characteristics are used as they prevail in the particular

month. In order to determine the number of persons who

ever or always were poor or participated in a program

during a given time period, the characteristics are used as

of the first month (wave) of the time period in question.

When looking at spells of program participation, the characteristics of persons experiencing the spells are as of the

month (wave) during which the spell began.

Aid to Families With Dependent Children (AFDC) and

General Assistance. Persons were considered participants in AFDC or General Assistance if they were identified

as primary recipients or if they were covered under other

persons’ allotment.

Federal and State rent assistance. Survey of Income and

Program Participation (SIPP) respondents were asked

whether their residence is owned by a local housing

authority or whether the Federal, State, or local government is paying part of the rent. A ‘‘yes’’ to either question

identified the respondent and others living at the same

residence as participants in a public or subsidized rental

housing program.

Food stamps. The questions on participation in the Food

Stamp Program in SIPP were designed to identify households in which one or more of the current members

received food stamps. Once a food stamp household was

identified, a question was asked to determine the number

of current household members covered by food stamps.

Questions also were asked about the number of months

food stamps were received and the total face value of all

food stamps received during the period.

Medicaid. The Medicaid question in SIPP attempted to

identify all adults who were covered by Medicaid. The term

‘‘covered’’ means enrolled in the Medicaid program; e.g.,

had a Medicaid medical assistance card or incurred medical bills which were paid for by Medicaid. In order to be

counted, the person did not have to receive medical care

paid for by Medicaid. Coverage was assigned in situations

where it was not reported but should have been; i.e., where

persons were categorically eligible through their reported

participation in other cash transfer programs.

Supplemental Security Income (SSI). A person was considered a participant in the SSI program during a given

month, if he/she received payments from the U.S. Government or from a State or local welfare office during that

month.

Survival analysis. Some of the estimates presented in

this report are distributions of spell duration for individuals

with different characteristics. We use a survival analysis

technique to derive these distributions and the resulting

estimates of median spell duration for persons observed

entering a particular program during the 32 months of the

panel. We consider only individuals who were present in

the survey all 32 months. One alternative would have been

to include all persons up until the time of attrition. It is,

however, extremely difficult to come up with appropriate

weights for such an analysis, and it was therefore not

attempted here.

Spells of program participation must have an observed

beginning; i.e., have to be preceded by 1 or more months

of ‘‘non’’ spells during the panel. Furthermore, while a spell

can be as short as one month, two spells must be more

than 1 month apart in order to be counted as separate

spells. If two potential spells are separated by only 1

month, they count as one spell. The connecting month is

counted as part of the resulting spell. A spell is observed

either until it ends or until it is right-censored. Since an

individual must have completed interviews for all months of

the panel in order to be included in the sample, rightcensoring occurs only if an individual is still participating in

the last month of the panel.

A–1
The probability of exiting a spell in month t, given that the

person was experiencing a spell in the beginning of that

month, is defined as

h(t)= exits(t)

prog(t! - (rcens(t)/2)

where exits(t) denotes the number of spell exits in month

t, prog(t) is the number of spells that were in progress in the

beginning of month t, and rcens(t) is the number of spells

which were right-censored in month t.

The survival rate in month t, which is the probability that

a spell lasts longer than t months, can then be written as

S(t)=

t

p

k=1(1-h(k))

The survival function evaluated at t gives the probability

that an entrant into a program is still participating in the

program t time periods later.

The median survival time or spell duration M can be

estimated by linear interpolation. Let [t, t+1) be the interval

such that S(t)>=.5 and S(t+1)<.5.

M 5 t 1

S~t!21/2

S~t!2S~t11!

Since a spell must be preceded by a period of nonparticipation, left censored spells of participation are not

included in our analysis. Observations are left censored

when the beginning of a spell of interest is not observed,

that is, a spell began at some time before the reference

period.

While dynamic estimates may be unbiased for spells

with observed beginnings in the reference period, there

remains concern about the deletion of left-censored spells

from such analyses. There may be particular characteristics of persons, associated with the experience of very long

spells, that preclude their inclusion in our sample. For

example, in our analysis, which is restricted to persons in

sample the entire period, selecting spells with observed

beginnings leads to a sample without those persons who

participated in a means-tested program from the first

month of life onward. Even if one defines the spells of those

‘‘born into participation’’ as spells with observed beginnings, the problem of unavailable appropriate weights

make their inclusion all but impossible. Studies of spells

with observed beginnings might result in reasonable estimates of spell distribution and median duration for such

spells with observed beginnings, but it might result in

downward biased estimates of the median duration of all

spells.

A–2
Appendix B.

Source and Accuracy Statement

SOURCE OF DATA

The Survey of Income and Program Participation (SIPP)

universe is the noninstitutionalized resident population

living in the United States. Field representatives interview

eligible persons who are at least 15 years of age at the time

of the interview. Not eligible to be in the survey are crew

members of merchant vessels; Armed Forces personnel

living in military barracks; institutionalized persons, such as

correctional facility inmates and nursing home residents;

and U.S. citizens residing abroad.

The SIPP sample for the 1991 panel is located in 230

Primary Sampling Units (PSU’s) each consisting of a

county or a group of contiguous counties. This report also

contains some data from the 1990 panel.1

For the 1991 panel, interviewing began in February,

March, April, or May of 1991 for four random subsamples,

respectively. For the remainder of the panel, interviews for

each person occurred every 4 months for a total of eight

interviews. At each interview, the reference period was the

4 months preceding the interview month.

Occupants of about 93 percent of all eligible living

quarters participated in the first interview of the panel. For

later interviews, field representatives interviewed only original sample persons and persons living with them. We

follow respondents who move during the panel. The Census Bureau automatically designated all first-interview noninterviewed households as noninterviews for all subsequent interviews.2

We classified a person as interviewed for the entire

panel and both calendar years based on the following two

definitions:3

1. Those for whom self, proxy, or imputed responses

were obtained for each reference month of all eight

interviews for the 1991 panel, and all three interviews

for each calendar year; or

2. Those for whom self or proxy responses were obtained

for the first reference month of the interview period and

responses exist for each subsequent month until they

were known to have died or moved to an ineligible

address (foreign living quarters, institutions, or military

barracks).

Everyone else is considered noninterview.4

Some estimates are based on monthly averages from

cross-sectional files. Nonresponse rates for the months on

the file vary from 10 percent to 21 percent.2

Some respondents did not respond to some of the

questions. Therefore, the overall nonresponse rate for

some items, especially sensitive income and money related

items, is higher than the person nonresponse rate.5

ESTIMATION

We used several stages of weight adjustments in the

estimation procedure to derive the SIPP longitudinal person weights. We gave each person a base weight equal to

the inverse of his/her probability of selection. We applied

two noninterview adjustment factors. One adjusted the

weights of interviewed persons in interviewed households

to account for households that were eligible for the sample

but which field representatives could not interview at the

first interview. The second compensated for person noninterviews occurring in subsequent interviews.6

We performed an additional stage of adjustment to

longitudinal person weights to reduce the mean square

error of the survey estimates. We accomplished this by

ratio adjusting the sample estimates to agree with monthly

Current Population Survey (CPS) type estimates of the

civilian (and some military) noninstitutional population of

the United States at the national level by demographic

characteristics including age, sex, and race, as of the

specified control date. We also controlled SIPP estimates

to independent Hispanic controls.2

ACCURACY OF ESTIMATES

We base SIPP estimates on a sample. The sample

estimates may differ somewhat from the values obtained

from administering a complete census using the same

1

P70-42.

2

‘‘SIPP 91: Source and Accuracy Statement for the Longitudinal Panel

File REVISION,’’ dated October 19, 1994. 3

‘‘Weighting of Persons for SIPP Longitudinal Tabulations,’’ paper by

Judkins, Hubble, Dorsch, McMillen, and Ernst in the 1994 Proceedings of

the Survey Research Methods Section, American Statistical Association.

4

‘‘Weighting Adjustment for Partial Nonresponse in the 1984 SIPP

Panel,’’ paper by Lepkowski, Kalton, and Kasprzyk in the 1989 Proceedings of the Survey Research Methods Section, American Statistical

Association. 5

Quality Profile for the Survey of Income and Program Participation,

May 1990, by T. Jabine, K. King, and R. Petroni. Available from Customer

Services, Data Users Services Division (301-457-1139). 6

Nonresponse Adjustment Methods for Demographic Surveys at the

U.S. Bureau of the Census, November 1988, Working Paper 8823, by

R. Singh and R. Petroni.

B–1
questionnaire, instructions, and enumerators. The difference occurs because a sample survey estimate is subject

to two types of errors: nonsampling and sampling. We can

provide estimates of the magnitude of the SIPP sampling

error, but this is not true of nonsampling error. The next few

sections describe SIPP nonsampling error sources, followed by a discussion of sampling error, its estimation, and

its use in data analysis.

Nonsampling variability. We attribute nonsampling errors

to many sources; they include but are not limited to the

following:

x Inability to obtain information about all cases in the

sample

x Inability or unwillingness on the part of the respondents

to provide correct information

x Errors made in collection (e.g., recording or coding the

data)

x Undercoverage

We used quality control and edit procedures to reduce

errors made by respondents, coders, and interviewers.7

Undercoverage in SIPP resulted from missed living

quarters and missed persons within sample households. It

is known that undercoverage varies with age, race, and

sex. Generally, undercoverage is larger for males than for

females and larger for Blacks than for non-Blacks. Ratio

estimation to independent age-race-sex population controls partially corrects for the bias resulting from survey

undercoverage. However, biases exist in the estimates

when persons in missed households or missed persons in

interviewed households have characteristics different from

those of interviewed persons in the same age-race-sex

group. Further, we did not adjust the independent population controls for undercoverage in the census.8

Comparability with other estimates. Exercise caution

when comparing data from this report with data from other

SIPP publications or with data from other surveys. Comparability problems are from varying seasonal patterns for

many characteristics, different nonsampling errors, and

different concepts and procedures.7

Sampling variability. Standard errors indicate the magnitude of the sampling error. They also partially measure the

effect of some nonsampling errors in response and enumeration, but do not measure any systematic biases in the

data. The standard errors mostly measure the variations

that occurred by chance because we surveyed a sample

rather than the entire population.

USES AND COMPUTATION OF STANDARD

ERRORS

Confidence intervals. The sample estimate and its standard error enable one to construct confidence intervals;

ranges that would include the average result of all possible

samples with a known probability.

Approximately 90 percent of the intervals from 1.645

standard errors below the estimate to 1.645 standard

errors above the estimate would include the average result

of all possible samples.

Approximately 95 percent of the intervals from 1.960

standard errors below the estimate to 1.960 standard

errors above the estimate would include the average result

of all possible samples.

The average estimate derived from all possible samples

is or is not contained in any particular computed interval.

However, for a particular sample, one can say with a

specified confidence that the confidence interval includes

the average estimate derived from all possible samples.

Hypothesis testing. One may also use standard errors

for hypothesis testing. Hypothesis testing is a procedure for

distinguishing between population characteristics using

sample estimates. The most common type of hypothesis

tested is (1) the population characteristics are identical

versus (2) they are different. One can perform tests at

various levels of significance, where a level of significance

is the probability of concluding that the characteristics are

different when, in fact, they are identical.

Unless noted otherwise, all statements of comparison in

the report passed a hypothesis test at the 0.10 level of

significance or better. This means that, for differences cited

in the report, the estimated absolute difference between

parameters is greater than 1.645 times the standard error

of the difference.

To perform the most common test, compute the difference XA - XB, where XA and XB are sample estimates of the

characteristics of interest. A later section explains how to

derive an estimate of the standard error of the difference XA

- XB. Let that standard error be sDIFF. If XA - XB is between

-1.645 times sDIFF and +1.645 times sDIFF, no conclusion

about the characteristics is justified at the 10- percent

significance level. If, on the other hand, XA - XB is smaller

than -1.645 times sDIFF or larger than +1.645 times sDIFF,

the observed difference is significant at the 10-percent

level. In this event, it is commonly accepted practice to say

that the characteristics are different. Of course, sometimes

this conclusion will be wrong. When the characteristics are,

in fact, the same, there is a 10-percent chance of concluding that they are different.

Note that as we perform more tests, more erroneous

significant differences will occur. For example, at the

10-percent significance level, if we perform 100 independent hypothesis tests in which there are no real differences,

it is likely that about 10 erroneous differences will occur.

Therefore, interpret the significance of any single test

cautiously.

7

P70-42.

8

Quality Profile for the Survey of Income and Program Participation,

May 1990, by T. Jabine, K. King, and R. Petroni. Available from Customer

Services, Data Users Services Division (301-457-1139).

B–2
Standard error parameters and tables and their

use. Most SIPP estimates have greater standard errors

than those obtained through a simple random sample

because we sampled clusters of living quarters for the

SIPP. To derive standard errors at a moderate cost and

applicable to a wide variety of estimates, we made a

number of approximations. We grouped estimates with

similar standard error behavior and developed two parameters (denoted ‘‘a’’ and ‘‘b’’) to approximate the standard

error behavior of each group of estimates. Because the

actual standard error behavior was not identical for all

estimates within a group, the standard errors we computed

from these parameters provide an indication of the order of

magnitude of the standard error for any specific estimate.

These ‘‘a’’ and ‘‘b’’ parameters vary by characteristic and

by demographic subgroup to which the estimate applies.

Methods for using these parameters and tables for

computation of standard errors are given in the following

sections. To calculate standard errors for estimates of

persons ever participating or persons participating all of 2

years, use the parameters in tables 1 and 2. To calculate

standard errors for estimates of average monthly participation, use the parameters in tables 3 and 4. The standard

errors for median monthly family benefits and median spell

duration have already been calculated and are in tables 5

and 6, respectively. The bases for percentages are in table 7.

Standard errors of estimated numbers. Approximate sx

using the formula,

sx 5 =ax2 1 bx (1)

Here x is the size of the estimate and a and b are the

parameters in tables 1 through 4 associated with the

particular type of characteristic. When calculating standard

errors for numbers from cross-tabulations involving different characteristics, use the factor or set of parameters for

the characteristic that will give the largest standard error.

Illustration. Suppose the 1991 SIPP estimates that approximately 34 million persons participated in a major meanstested assistance program in an average month during

1992. The appropriate ‘‘a’’ and ‘‘b’’ parameters from table 4

are:

a = –0.0001063 b = 25,616

Using formula (1), the approximate standard error is

sx 5 =~–0.0001063!~33,954,000!

2 1 ~25,616!~33,954,000! 5 864,000

The 90-percent confidence interval is from 32,533,000

to 35,375,000. Therefore, a conclusion that the average

estimate derived from all possible samples lies within a

range computed in this way would be correct for roughly 90

percent of all samples.

Standard errors of estimated percentages. The reliability of an estimated percentage, computed using sample

data for both numerator and denominator, depends on the

size of the percentage and its base. When the numerator

and denominator of the percentage have different parameters, use the parameter from tables 1 through 4 indicated

by the numerator.

Approximate the standard error by the formula:

s~x,p! 5 Îb

x

~p!~1002p! (2)

Here x is the total number of persons in the base of the

percentage, p is the percentage (0 ≤ p ≤ 100), and b is the

‘‘b’’ parameter in tables 1 through 4 associated with the

characteristic in the numerator of the percentage.

Illustration. As shown in text table A, the 1991 SIPP

estimates that 4.3 percent of the population received food

stamps each month of 1991 and 1992. To find the base for

the percentage, use table 7 of this source and accuracy

statement. In this example, the base is 243,348,000. The

appropriate ‘‘b’’ parameter from table 2 is

b = 26,142

Using formula (2), the approximate standard error is

sx 5 Î( 26,142

243,348,000)~4.3!~10024.3! 5 0.2 percent

The 90-percent confidence interval is from 4.0 to 4.6

percent. Therefore, a conclusion that the average percentage derived from all possible samples lies within a range

computed in this way would be correct for roughly 90

percent of all samples.

B–3
Table B–1. SIPP Generalized Variance Parameters for Estimates From the 1990 Longitudinal File

Characteristics

of persons

Weights

1990 panel 1990 calendar year 1991 calendar year

ababa b

TOTAL1

18+ program participation ...... -0.0001077 18 329 -0.0000965 16 418 -0.0001002 17 051

All others .................... -0.0000985 22 724 -0.0000882 20 356 -0.0000916 21 140

White ........................ -0.0001093 25 185 -0.0000979 22 560 -0.0001016 23 429

Black ........................ -0.0002202 6 076 -0.0001972 5 443 -0.0002048 5 652

Hispanic origin2 ............... -0.0002931 6 076 -0.0002626 5 443 -0.0002727 5 652

1

Use the ‘‘All Others’’ parameter for 0+ program participation and any other type of tabulation not covered by the characteristic ‘‘18+ program

participation.’’ 2

Persons of Hispanic origin may be of any race.

Table B–2. SIPP Generalized Variance Parameters for Estimates From the 1991 Longitudinal File

Characteristics

of persons

Weights

1991 panel 1991 calendar year 1992 calendar year

ababa b

TOTAL OR WHITE

18+ program participation ...... -0.0001592 26 142 -0.0001484 24 380 -0.0001531 25 143

All others ..................... -0.0001345 32 413 -0.0001254 30 228 -0.0001294 31 174

BLACK

Poverty ...................... -0.0007588 22 299 -0.0007076 20 796 -0.0007298 21 447

All others ..................... -0.0004081 11 992 -0.0003806 11 183 -0.0003925 11 533

Table B–3. SIPP Indirect Generalized Variance Parameters for Annual Estimates Based on Monthly Averages

From the 1990 Cross-Sectional Files

Characteristics

of persons

1990 calendar year 1991 calendar year

aba b

TOTAL

All others................................................. -0.0000663 15 294 -0.0000723 16 671

Table B–4. SIPP Indirect Generalized Variance Parameters for Annual Estimates Based on Monthly Averages

From the 1991 Panel Cross-Sectional Files

Characteristics of

persons

1991 calendar year 1992 calendar year

aba b

TOTAL OR WHITE

All others................................................. -0.0000975 23 501 -0.0001063 25 616

B–4
Table B–5. Standard Errors of Median Monthly Family Benefits in the 1991 SIPP Panel by Selected

Characteristics

(In 1992 dollars)

Characteristic

Standard error of median monthly family benefits

All programs AFDC Food stamps

1991 1992 1991 1992 1991 1992

Total . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0 3.5 3.5 3.0 1.5 2.0

RACE AND HISPANIC ORIGIN

White . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.0 4.0 7.0 2.5 1.0 0.5

Black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5 5.5 3.5 4.0 0.5 0.5

Hispanic origin1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 14.0 2.5 1.0 2.5 6.0

AGE

Under 18 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.5 8.5 9.0 8.0 2.0 2.5

18 to 64 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 5.5 3.0 5.5 4.0 2.0

65 years and over . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.0 6.5 28.5 20.5 1.5 3.5

EMPLOYMENT AND LABOR FORCE STATUS (18+)

Employed full time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 9.5 22.5 19.0 3.5 6.5

Employed part time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 11.0 14.0 22.5 9.5 7.5

Unemployed ............................................ 16.5 19.0 3.5 22.0 6.0 4.5

Not in labor force. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.0 3.0 3.5 7.5 3.5 2.5

DISABILITY STATUS (15-69)

With a work disability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.5 4.0 12.5 8.5 4.0 4.5

With no work disability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0 7.0 8.5 8.0 3.0 3.5

FAMILY STATUS

In families . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 5.5 4.0 4.0 2.0 1.5

In married-couple families . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5 7.5 8.0 5.0 2.0 3.0

In families with a female householder, no spouse present . . . 3.0 4.0 3.5 2.5 2.5 2.0

Unrelated individuals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.5 8.0 4.0 0.5 2.0 1.5

1

Persons of Hispanic origin may be of any race.

Table B–6. Standard Errors of Median Spell Duration for Persons Experiencing Spells in the 1991 SIPP Panel by

Selected Characteristics

Characteristic

Standard error of spell duration medians

All programs AFDC Food stamps

Total .......................................................... 0.26547 0.49443 1.18046

RACE AND HISPANIC ORIGIN

White.............................................................. 0.29847 0.98879 0.51125

Black .............................................................. 2.39501 1.02666 1.67975

Hispanic origin1..................................................... 0.46185 1.41134 3.89635

AGE

Under 18 years ..................................................... 0.41482 0.52885 1.17543

18 to 64 years...................................................... 0.31579 1.28218 0.57590

65 years and over .................................................. 4.19450

EMPLOYMENT AND LABOR FORCE STATUS (18+)

Employed full time .................................................. 2.26294 0.28511 0.81229

Employed part time ................................................. 0.95997 6.50759 0.89904

Unemployed ....................................................... 0.93658 0.98807 0.83814

Not in labor force ................................................... 2.21738 12.0324 2.55189

DISABILITY STATUS (15-69)

With a work disability................................................ 14.3854 1.47068 10.8277

With no work disability .............................................. 0.33995 0.94395 0.68706

FAMILY STATUS

In families.......................................................... 0.27074 0.50702 1.30211

In married-couple families.......................................... 0.32720 0.54448 0.60894

In families with a female householder, no spouse present ............. 1.74421 1.98670 1.80215

Unrelated individuals ................................................ 2.29520 0.56485 2.39797

1

Persons of Hispanic origin may be of any race.

B–5
Table B–7. Bases for Estimates

Characteristic

Average monthly participation Persons who participated 1 or

more months

Persons who

participated all

24 months of

1991 1992 1991 1992 1991 and 1992

All persons . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 249 904 253 642 247 187 250 020 243 348

Race and Hispanic Origin

White. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 208 344 211 459 205 820 208 483 202 995

Black . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 168 31 812 30 878 31 237 30 232

Hispanic origin1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 742 23 838 22 885 24 442 22 386

Age

Under 18 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66 019 67 639 66 745 67 626 67 078

18 to 64 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153 481 155 331 151 969 153 519 149 699

65 years and over . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 404 30 672 28 472 28 875 26 571

Employment and Labor Force Status (persons 18

years and over)

Employed full time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95 077 95 347 94 210 94 010 93 767

Employed part time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 707 22 128 22 036 22 779 21 906

Unemployed. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 810 7 543 6 955 7 301 6 353

Not in labor force . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 290 60 984 57 241 58 303 54 245

Disability Status (persons 15 to 69 years)

With a work disability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 076 27 493 26 523 25 386 25 125

With no work disability. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145 941 148 417 145 833 148 517 144 645

Family Status

In families . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 213 344 217 475 212 391 215 902 209 870

In married-couple families. . . . . . . . . . . . . . . . . . . . . . . . . 170 505 172 919 170 599 173 164 169 481

In families with a female householder, no spouse

present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 528 36 990 35 142 36 434 34 219

Unrelated individuals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 561 36 168 34 795 34 118 33 478

1

Persons of Hispanic origin may be of any race.

B–6