U S C E N S U S B U R E A U

Helping You Make Informed Decisions

U.S. Department of Commerce

Economics and Statistics Administration

U.S. CENSUS BUREAU

Dynamics of Economic Well-Being:

Moving Up and Down the Income

Ladder, 1998 to 1999

Household Economic Studies

P70-100

Issued April 2005

Current

Population

Reports

By 

Wilfred T. Masumura

and

John J. Hisnanick

From year to year, the financial

well-being of most Americans

changes. Summary measures,

such as median income, reflect

the overall net gain or loss in

income, but do not indicate the

amount of movement up and

down the income ladder. This

report focuses on the issue of

movements within the income

ladder using data that represent the civilian noninstitutionalized population of the United

States as measured by the

1996 panel of the Survey of

Income and Program

Participation (SIPP).1 (See text

box “SIPP—A Longitudinal

Survey” for more information

concerning SIPP.)

The measure of economic wellbeing used in this report is the

income-to-poverty ratio—called

the income ratio here—that is,

the ratio of a person’s annual

1 The data in this report were collected from April 1996 through March 2000

in the 1996 panel of the Survey of

Income and Program Participation (SIPP).

The population represented (population

universe) is the civilian noninstitutionalized population living in the United

States. This report is an update of previous reports—P70-65: “Dynamics of

Economic Well-Being: Income, 1993 to

1994, Moving Up and Down the Income

Ladder,” July 1998; P70-56: “Dynamics

of Economic Well-Being: Income, 1992 to

1993, Moving Up and Down the Income

Ladder,” June 1996; and P70-49:

“Dynamics of Economic Well-Being:

Income, 1991 to 1992,” August 1995.

Due to the redesign of the 1996 SIPP

panel, the reader should use caution in

making comparisons between the 1996

SIPP panel and earlier SIPP panels.

SIPP—A Longitudinal Survey

SIPP is a longitudinal survey that captures

changes for the same individual over a period

of time. The 1996 SIPP panel attempted to

interview 36,700 households 12 times at 

4-month intervals from April 1996 through

March 2000, following all members of the

original sample household. Not all households responded to the survey for all twelve

interviews that are needed to create a full

picture over the 4 years of the panel. Efforts

are made during the life of the panel to ensure

that the remaining sample is representative of

the noninstitutionalized population of the

United States. The SIPP weighting procedure

uses ratio estimation, whereby sample estimates are adjusted to independent estimates

of the national population by age, race, sex,

and Hispanic origin. This weighting partially

corrects for bias due to undercoverage and

attrition, but biases may still be present when

people who are missed by the survey differ

from those interviewed in ways other than

age, race, sex, and Hispanic origin. How this

weighting procedure affects other variables in

the survey is not precisely known. All of these

considerations affect comparisons across

different surveys or data sources. 

Demographic and economic characteristics

were gathered during each interview, whereas

special topics varied from interview to interview. The SIPP collects more detailed data than

any other national survey on general income

sources and amounts; program eligibility,

access, and participation; transfer income; and

in-kind benefits. More information on SIPP can

be found at <www.sipp.census.gov/sipp/>.
family income to the family’s poverty threshold.2 An income ratio of

less than 1.0 indicates a person is

in poverty, whereas an income ratio

greater than 1.0 indicates that a

person’s income is above the

poverty threshold. Changes in this

measure of well-being are due not

only to increases or declines in

income but also to changes in personal circumstances, such as

changes in the number of workers

in a household, marital and family

status, and other elements of

household composition. This report

focuses on people for whom poverty status is defined. In the following discussion, people aged 15 and

older is the unit of analysis, using

their individual characteristics, or

the characteristics of their family or

household, as appropriate.

HISTORICAL COMPARISON

OF CHANGES IN THE

INCOME RATIO

A large majority of the population,

roughly three-fourths to four-fifths,

experiences either an increase or a

decline in their income ratio of at

least 5 percent or more from one

year to the next.3 Figure 1 shows

that over the last two decades of

the twentieth century, the percentage of people experiencing a

change of 5 percent or more in

their income ratio increased from

2 U.S. Census Bureau

2 Following the Office of Management and

Budget’s (OMB) Statistical Policy Directive 14,

the Census Bureau uses a set of money

income thresholds that vary by family size

and composition to determine who is in

poverty. Guidelines are available at the following Census Bureau Web site: 

<www.census.gov/hhes/www/poverty.html>. 3 The estimates in this report (which may

be shown in text, figures, and tables) are

based on responses from a sample of the

population and may vary from the actual

values because of sampling variability or

other factors. As a result, apparent differences between estimates for two or more

groups may not be statistically significant.

All comparative statements have undergone

statistical testing and are significant at the

90-percent confidence level unless 

otherwise noted.

Figure 1.

Percent Distribution of Individuals by Year-to-Year 

Changes in Their Income Ratios: 1984 to 1999

Note: Longitudinal data are not available for 1986-87, 1988-89, 1989-90, 1994-95, 

and 1995-96.

Source: U.S. Census Bureau, Survey of Income and Program Participation, 1984, 1985, 

1987, 1990, 1992, 1993, and 1996 Panels.

Increased 5 percent or more

Changed less than 5 percent

Decreased 5 percent or more

1998 to 1999

1997 to 1998

1996 to 1997

1993 to 1994

1992 to 1993

1991 to 1992

1990 to 1991

1987 to 1988

1985 to 1986

1984 to 1985

42.3

24.1

33.6

47.1

22.6

30.3

44.2

23.5

32.3

36.3

23.4

40.3

39.7

22.4

37.9

38.7

21.9

39.4

40.5

22.7

36.8

46.1

17.8

36.1

47.6

19.5

32.9

45.5

20.1

34.4
76 percent during 1984 to 1985

(the first two calendar years of SIPP)

to 82 percent during 1996 to

1997.4 This variability in economic

status leveled off with about 

81 percent of people for 1997 and

1998 and 80 percent of people

from 1998 to 1999 experiencing

changes of 5 percent or more in

their income ratio.5 During most of

this period, the percentage of people seeing an improvement in their

income ratio outpaced the percentU.S. Census Bureau 3

4 Income ratio changes of less than 5 percent from year to year are not counted as

either an increase or a decrease, but are

regarded as “stable.” Inflation adjustment is

implicit because the poverty thresholds are

adjusted annually using the Consumer 

Price Index. 5 The time trend for the percent of people

who experience changes of 5 percent or

more in their income ratio was tested using

a regression model. The slope of the time

coefficient was positive and statistically

significant. 

age with a decline, with the exception of the period 1990 to 1993.

The years 1984 to 1999 can be

divided into three time periods.

First, the three pairs of years in the

late 1980s were a period in which

increases in the income ratio outnumbered declines. Second, the

first half of the 1990s was characterized by little difference between

the proportion of increases and

declines in income ratios. Finally,

in the late 1990s, increases in 

the income ratio once again

exceeded decreases.

In looking at the proportion of

people who experienced an annual

change in their income ratio from

1996 to 1999, while the proportions are different, the magnitudes

in each direction of change

between the years are similar (see

Figure 1). Because of this similarity, the following discussion of

changes in the income ratios of

individuals focuses on the most

recent years of data available,

1998 to 1999.

The frequency of increases and

declines in the income ratio vary

by characteristics of the population. As tracked by this report and

previous reports on the dynamics

of economic well-being, some segments of the population are more

likely to experience growth in their

income ratios, while other parts

are more likely to experience financial declines. Prior reports have

identified a number of characteristics consistently associated with

these increases and declines.

The change in the income ratio for

an individual is related to the level

of the income ratio in the first

year. As Figure 2 shows, people

with a higher income ratio in 1998

were more likely to experience an

income ratio decline in the next

year. Of those individuals with an

income ratio of 4.0 or more, 

42 percent experienced a decline

in their income ratio from 1998 to

1999; of those with an income

ratio less than 1.0, 26 percent had

declines between 1998 and 1999.

Conversely, the lower one’s income

ratio, the more likely the income

ratio is to rise from one year to the

next. Of those with an income

ratio less than 1.0, 55 percent saw

their income ratio rise from 1998

to 1999; while of those with an

income ratio of 4.0 or more, 

37 percent experienced a rise in

their income ratio.

Figure 2.

Percent Distribution of Changes in the 

Income Ratio for Individuals by Their Initial 

Income Ratio: 1998 to 1999

Source: U.S. Census Bureau, Survey of Income and Program Participation, 1996 Panel.

Income ratio: 4.0 or more

Income ratio: 2.0 to 3.9

Income ratio: 1.0 to 1.9

Income ratio: less than 1.0

Declined 5 percent

or more

Changed less than

5 percent

Increased 5 percent

or more

42.3

32.8

28.1

25.6

20.7

19.5

20.2

19.9

37.0

47.7

51.7

54.5
4 U.S. Census Bureau

Table 1.

Changes in Income Ratio by Selected Characteristics: 1998 to 1999

Characteristics

Total

(thousands)

Declined 5 percent

or more

Changed less than

5 percent

Increased 5 percent

or more

Percent

90 percent

confidence

interval (+/-) Percent

90-percent

confidence

interval (+/-) Percent

90-percent

confidence

interval (+/-)

All People . . . . . . . . . . . . . . . . . . . . . . . . . . .

INCOME RATIO IN 1998

273,326 34.4 0.4 20.1 0.3 45.5 0.4

Less than 1.0 ........................ 26,684 25.6 1.2 19.9 1.1 54.5 1.3

1.00 to 1.99 . ......................... 52,901 28.1 0.9 20.2 0.8 51.7 0.9

2.00 to 3.99 . ......................... 100,155 32.8 0.6 19.5 0.5 47.7 0.7

4.00 or more .........................

WORK EXPERIENCE

(People 18 and over)

Year-round, full-time in 1998 to not

93,585 42.3 0.7 20.7 0.6 37.0 0.7

year-round, full-time in 1999 ..........

Not year-round, full-time in 1998 to

11,233 54.6 2.1 14.4 1.4 30.9 0.9

year-round, full-time in 1999 ..........

NUMBER OF WORKERS IN FAMILY

12,698 23.7 1.6 12.9 1.3 63.5 1.9

Fewer workers in 1999 than 1998 ...... 26,316 64.0 1.3 9.8 0.8 26.1 1.2

More workers in 1999 than 1998 .......

MARITAL STATUS

From married in 1998 to any other

30,561 18.0 1.0 11.0 0.8 71.0 1.1

marital status in 1999 ................

From any other marital status in 1998 to

2,169 60.8 4.6 11.2 3.0 28.0 4.2

married in 1999 .....................

FAMILY STATUS

From married-couple family in 1998 to

3,157 31.0 3.6 7.4 2.0 61.6 3.8

other family type in 1999 .............

From other family type in 1998 to

2,756 61.1 4.1 9.4 2.4 29.6 3.8

married-couple family in 1999 . . .......

FAMILY COMPOSITION

No change in number of adults:

2,014 29.6 4.5 7.6 2.6 62.8 4.7

Fewer children in 1999 than 1998 .... 4,186 27.9 3.0 16.4 2.5 55.7 3.4

More children in 1999 than 1998 .....

No change in number of children:

7,901 62.0 2.4 14.5 1.7 23.6 2.1

Fewer adults in 1999 than 1998 . . .... 12,653 52.4 1.9 10.6 1.2 37.0 1.9

More adults in 1999 than 1998 .......

SEX

8,434 24.5 2.0 10.5 1.5 65.0 2.3

Women ............................. 141,545 34.6 0.5 20.4 0.5 45.0 0.6

Men . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

RACE AND HISPANIC ORIGIN

131,781 34.2 0.6 19.8 0.5 45.9 0.6

White ............................... 225,544 34.2 0.4 20.6 0.4 45.2 0.5

White, non-Hispanic .................. 199,988 34.5 0.5 20.8 0.4 44.7 0.5

Black ............................... 34,753 34.6 1.1 17.9 0.9 47.4 1.2

Hispanic (of any race) .................

AGE (in 1998)

27,433 32.0 1.0 19.0 1.0 48.9 1.3

Under 18 years ...................... 64,969 32.5 0.8 19.2 0.7 48.3 0.9

18 to 24 years ....................... 25,758 35.4 1.3 13.7 0.9 50.9 1.4

25 to 44 years ....................... 86,747 33.7 0.7 18.9 0.6 47.5 0.7

45 to 64 years ....................... 61,511 36.2 0.8 19.5 0.7 44.3 0.9

65 years and over .................... 34,341 36.0 1.1 30.9 1.1 33.1 1.1

Source: U.S. Census Bureau, Survey of Income and Program Participation, 1996 Panel.
CHANGES IN PERSONAL in 1999 than in 1998, 64 percent

CIRCUMSTANCES AND experienced declines in their

CHANGES IN THE income ratio, compared with 

INCOME RATIO 18 percent of people in the opposite situation. Among workers 18 and older who

changed from not being employed The makeup of families has a

year-round, full-time in 1998 to strong effect on the income ratio;

year-round, full-time employment this was true for family status

in 1999, 64 percent experienced (being in a married-couple family

an increase in their income ratio; or not) and for family composition

while among workers whose as indicated by the number of chilemployment experience was the dren or the number of adults.

reverse, 31 percent experienced a Among people (of any age) in

gain in their income ratio (Table 1). married-couple families in 1998

Similarly, among year-round, full- but not 1999, 61 percent saw their

time workers in 1998 who were income ratio decline, compared

not so employed in 1999, 55 per- with 30 percent of people who

cent saw their income ratio became part of married-couple

decline; while 24 percent of work- families in 1999. The income ratio

ers in the opposite employment increased for 63 percent of people

situation saw a decline in their who became part of married-couincome ratio. ple families in 1999 and for 

30 percent of those who were no Being in a family with more work- longer part of married-couple fami- ers in 1999 than in 1998 is associlies in 1999. ated with an increase in the

income ratio—71 percent had Having a larger number of children

increases in their income ratio; in the second year than the first

while 26 percent of people in the was associated with a lower

opposite situation had such income ratio. With the same

increases (see Figure 3). Similarly, income, the income ratio declines among individuals in families with when families get larger, for fewer year-round, full-time workers example when they have more

children. Of people in families

with more children in 1999 than

1998, 62 percent experienced a

decline in their income ratio, while

this was the case for 28 percent

with fewer children in 1999.

Among people in families with

fewer children in 1999 than 1998,

56 percent had a higher income

ratio in 1999, compared with 

24 percent with more children 

in 1999.

The data for the number of adults

in a family show similar patterns

to those for marital status. As one

would expect, more adults implies

more potential wage earners.

Thus, of people residing in families

with more adults in 1999 than in

1998, 65 percent realized gains in

their income ratio; whereas 37 percent of those in the opposite situation experienced a rise in their

income ratio. Among people in

families with fewer adults in 1999

than 1998, 52 percent experienced

declines in their income ratio; compared with 25 percent of those in

the situation where there were

more adults in 1999 than in 1998.

Among the five age cohorts examined here, fewer individuals aged

65 and older experienced an

increase in their income ratio 

(33 percent) than any other age

group. Those 65 and older also

had the largest proportion with a

stable income ratio from one year

to the next, 31 percent. These

results may be due in large part to

this group often having income

sources that are fixed, such as

pensions and other retirement

benefits. Even among this age

cohort, about two-thirds experienced year-to-year changes in their

income ratio.

Among the American population,

one’s sex had no effect on the

change in one’s income ratio. As

demonstrated in Table 1, the same

U.S. Census Bureau 5

Figure 3.

Percent Distribution of Changes in the Income Ratio 

for Individuals by the Number of Workers 

in the Family: 1998 to 1999

Source: U.S. Census Bureau, Survey of Income and Program Participation, 1996 Panel.

More workers in 1999 than 1998

Fewer workers in 1999 than 1998

Declined 5 percent

or more

Changed less than

5 percent

Increased 5 percent

or more 26.1

71.0

11.0

9.8

18.0

64.0
6 U.S. Census Bureau

Table 2.

Changes in Income Ratio by Receipt of Selected Types of Income: 1998 to 1999

Household income source Number of

people in

households

(thousands)

Declined 5 percent

or more

Changed less than

5 percent

Increased 5 percent

or more

Percent

90-percent

confidence

interval

(+/-) Percent

90-percent

confidence

interval

(+/-) Percent

90-percent

confidence

interval (+/-)

EARNINGS

Had earnings in 1999 but not 1998 ....... 3,145 16.9 2.9 14.5 2.7 68.6 3.6

Had earnings in 1998 but not 1999 .......

ASSET INCOME

4,580 73.2 2.9 11.1 2.0 15.7 1.1

Had asset income in 1999 but not 1998 . . . 8,635 25.5 2.1 20.1 1.9 54.4 2.3

Had asset income in 1998 but not 1999 . . .

UNEMPLOYMENT INSURANCE

11,729 44.6 2.0 13.4 1.4 42.0 2.0

Received benefits in 1999 but not 1998 . . . 8,227 44.3 2.4 12.2 1.6 42.5 2.4

Received benefits in 1998 but not 1999 . . .

PENSION AND PRIVATE DISABILITY

INCOME

10,361 36.8 2.1 14.3 1.5 48.9 2.1

Received benefits in 1999 but not 1998 . . . 9,535 31.4 2.1 9.9 1.3 58.7 2.2

Received benefits in 1998 but not 1999 . . .

SOCIAL SECURITY (AND RAILROAD

RETIREMENT)

5,949 57.8 2.8 10.7 1.8 31.5 2.6

Received benefits in 1999 but not 1998 . . . 5,336 37.9 2.9 9.8 1.8 52.3 3.0

Received benefits in 1998 but not 1999 . . .

MEANS-TESTED BENEFITS1

3,788 49.7 3.6 13.2 2.4 37.1 3.4

Received benefits in 1999 but not 1998 . . . 9,548 37.7 2.2 15.0 4.6 47.3 2.2

Received benefits in 1998 but not 1999 . . .

MEDICAID

10,217 36.4 2.1 15.7 5.3 47.9 2.2

Received aid in 1999 but not 1998 ........ 9,482 37.8 2.2 16.3 1.7 45.8 2.2

Received aid in 1998 but not 1999 ........

TEMPORARY ASSISTANCE FOR

NEEDY FAMILIES (TANF) AND

GENERAL ASSISTANCE

10,441 35.7 2.1 14.6 1.5 49.7 2.1

Received aid in 1999 but not 1998 ........ 1,071 36.2 6.4 17.0 5.0 46.8 6.7

Received aid in 1998 but not 1999 ........

SUPPLEMENTAL SECURITY INCOME

(SSI)

4,606 39.2 3.2 12.7 2.1 48.1 3.2

Received aid in 1999 but not 1998 ........ 2,841 27.6 3.7 18.8 3.2 53.6 4.1

Received aid in 1998 but not 1999 ........

FOOD STAMPS

2,820 47.5 4.1 15.5 3.0 37.0 4.0

Received stamps in 1999 but not 1998 . . . . 4,429 37.6 3.2 16.8 6.4 45.6 3.3

Received stamps in 1998 but not 1999 . . . . 6,314 27.4 2.5 13.3 1.9 59.3 2.7

1

Means-tested benefits include Temporary Assistance for Needy Families (TANF), General Assistance, Supplemental Security Income

(SSI), Medicaid, and food stamps.

Source: U.S. Census Bureau, Survey of Income and Program Participation, 1996 Panel.
percentage of men and women had

increases, decreases, and no

changes in their income ratios

between 1998 and 1999. 

Among the racial and ethnic

groups examined here, 45 percent

of non-Hispanic Whites experienced increases in their income

ratios from 1998 to 1999 compared with 47 percent of Blacks

and 49 percent of Hispanics.6

CHANGES IN INCOME

SOURCES AND CHANGES IN

THE INCOME RATIO

The appearance or disappearance

of a particular income source is

often associated with an increase

or decrease in the income ratio.

The following discussion presents

information on various sources of

U.S. Census Bureau 7

6 Hispanics may be any race. For example, in the 1996 SIPP Panel, 12 percent of the

White population, 3 percent of the Black

population, 16 percent of the American

Indian and Alaska Native population, and 

3 percent of the Asian and Pacific Islander

population also reported being Hispanic.

The group Asians and Pacific Islanders and

the group American Indians and Alaska

Natives make up 3.1 percent of the sample;

data about them are not shown in this report

because their sample sizes are too small.

The percent of Blacks and Hispanics that

experienced an increase in their income ratio

is not statistically different.

income and how they relate to

economic well-being as measured

by movements in an individual’s

income ratio from one year to 

the next.

Income from earnings had a large

effect on the income ratio. In

1999, 94 percent of income was

from earnings. As shown in 

Figure 4, among people who lived

in households where someone

received earnings in 1999 but not

in 1998, 69 percent showed gains

in their income ratio, while for

those in the opposite situation, 

16 percent experienced an increase

in their income ratio. Similarly, of

those who lived in a household

where someone received earnings

in 1998 but not in 1999, 73 percent experienced a decline in their

income ratio, compared with 

17 percent of people in the 

reverse situation.

Income from assets had some

impact on the income ratio. In

1999, 3 percent of income was

from assets. Of people living in

households that received asset

income in 1999 but not in 1998,

54 percent experienced an increase

in their income ratio, compared

with 42 percent of people who

received asset income in 1998 but

not in 1999. Declines in the

income ratio were greater among

people living in households without asset income in 1999 but with

it in 1998 than among those who

had income from assets in 1999

but not in 1998—45 percent compared with 26 percent (Table 2).

Income from pensions and disability benefits was also relevant. For

people in households where someone obtained income from pensions and disability benefits in

1999 but not 1998, 59 percent

experienced an increase in their

income ratio; this was the case for

32 percent of those in households

receiving pension and disability

benefits in 1998 but not in 1999.

By comparison, 58 percent of individuals in households that received

income from pensions and disability benefits in 1998 but not in

1999, and 31 percent in households that received this type of

income in 1999 but not in 1998,

experienced a decline in their

income ratio.

About 52 percent of people in

households receiving social security payments in 1999 but not 1998

experienced an increase in their

income ratio, compared with 

37 percent of people who received

social security payments in 1998

but not in 1999. For those in

households receiving social security payments in 1998 but not 1999,

50 percent experienced a decline

in their income ratio; while 38 percent of those in households receiving social security payments in

1999 but not in 1998 experienced

a decline in their income ratio.

Various forms of means-tested

financial assistance are made available to people with low incomes.

For the years 1998 and 1999,

households starting or ending

Figure 4.

Percent Distribution of Changes in the 

Income Ratio for Individuals by the Availability 

of Household Earnings: 1998 to 1999

Source: U.S. Census Bureau, Survey of Income and Program Participation, 1996 Panel.

Household had earnings in 1999 but not in 1998

Household had earnings in 1998 but not in 1999

Declined 5 percent

or more

Changed less than

5 percent

Increased 5 percent

or more

16.9

73.2

14.5

11.1

68.6

15.7
receipt of one or more of the

means-tested benefits examined

here were not differentially related

to increases and declines in the

income ratios of people in those

households.7 As Table 2 shows, 

47 percent of people in households

that received one or more types of

means-tested benefits in 1999 but

not in 1998 experienced an

increase in their income ratio. By

comparison, 48 percent of people

in households that received one or

more types of means-tested benefits in 1998 but not in 1999 experienced an increase in their income

ratio. Similarly, 38 percent of

those people in households that

received one or more types of

means-tested benefits in 1999 but

not in 1998, and 36 percent of

people in households that received

benefits from one or more types of

means-tested benefits in 1998 but

not in 1999, experienced a

decrease in their income ratio.

The results varied for specific

types of benefits. Households that

started receiving or lost income

from Temporary Assistance for

Needy Families (TANF) and General

Assistance had no differential association with changes in their

members’ income ratios, as shown

in Table 2. TANF is a federal program created by the Personal

Responsibility and Work

Opportunity Reconciliation Act of

1996 that delivers federal welfare

funds to states in a single block

grant. It replaced the former Aid

to Families with Dependent

Children (AFDC), Emergency

Assistance (EA), and Job

Opportunities and Basic Skills institutions and nursing homes 

(JOBS) Training programs. (91 percent of the 4.1 million

institutionalized population in The Supplemental Security Income Census 2000). (SSI) program provides monthly

payments to people who are aged, ACCURACY OF THE

blind, or disabled; it requires a ESTIMATES

means test for eligibility, including

Statistics from surveys are subject a limit on current assets. Unlike

to sampling and nonsampling the results for means-tested beneerror. All comparisons presented fits such as TANF and General

Assistance, among people in in this report have taken sampling

error into account and are signifi- households receiving SSI in 1999

cant at the 90-percent confidence but not 1998, a majority (54 perlevel. This means the 90-percent cent) experienced an increase in

confidence interval for the differ- their income ratio, compared with

ence between the estimates being one-third (37 percent) in the

compared does not include zero. reverse situation.

Nonsampling errors in surveys may

The food stamp program is the be attributed to a variety of

major national program that pro- sources, such as how the survey

vides food vouchers to low-income was designed, how respondents

and low-resource households. Of interpret questions, how able and

those people living in households willing respondents are to provide

that received food stamps in 1999 correct answers, and how accuratebut not in 1998, 38 percent experi- ly the answers are coded and clasenced a decrease in their income sified. The Census Bureau employs

ratio, while 27 percent of those in quality control procedures throughhouseholds that stopped receiving out the production process includfood stamps in 1999 experienced ing the overall design of surveys,

such a decrease. A majority the wording of questions, review

(59 percent) of people living in of the work of interviewers and

households that received food coders, and statistical review of

stamps in 1998 but not in 1999 reports to minimize these errors. 

experienced an increase in their

income ratio, compared with 46 The Survey of Income and Program

Participation weighting procedure percent of people who lived in

uses ratio estimation, whereby households that received food

sample estimates are adjusted to stamps in 1999 but not in 1998. 

independent estimates of the

SOURCE OF THE DATA national population by age, race,

sex, and Hispanic origin. This The population represented (the weighting partially corrects for population universe) in the 1996 bias due to undercoverage and Survey of Income and Program attrition, but biases may still be Participation (SIPP) is the civilian present when people who are noninstitutionalized population liv- missed by the survey differ from ing in the United States. The data those interviewed in ways other in this report were collected from than age, race, sex, and Hispanic April 1996 until March 2000. The origin. How this weighting proce- institutionalized population, which dure affects other variables in the

is excluded from the population survey is not precisely known. All

universe, is composed primarily of of these considerations affect

the population in correctional

8 U.S. Census Bureau

7 Means-tested benefits are financial

assistance that requires income and/or

assets of the individual or family to be

below specified thresholds in order to qualify for benefits. Means-tested benefits examined here are Temporary Assistance for

Needy Families (TANF), General Assistance,

Supplemental Security Income (SSI),

Medicaid, and food stamps.
comparisons across different Additional information on the SIPP USER COMMENTS

surveys or data sources. can be found at the following The Census Bureau welcomes the Web site: For further information on the comments and advice of users of

source of the data and accuracy of <www.sipp.census.gov/sipp/> its data and reports. If you have

the estimates including standard (SIPP main Web site); suggestions or comments, please

errors and confidence intervals, go send an e-mail inquiry to: <www.sipp.census.gov/sipp to <www.sipp.census.gov/sipp <hhes-info@census.gov> or contact /workpapr/wp230.pdf> /sourceac/s&a96_040501.pdf> or John J. Hisnanick, Chief, (SIPP Quality Profiles); contact Dennis Sissel of the Census Longitudinal Income Statistics

Bureau’s Demographic Statistical <www.sipp.census.gov/sipp Branch, via e-mail at 

Methods Division via e-mail at <john.j.hisnanick@census.gov> or /usrguide/sipp2001.pdf> 

<charles.d.sissel@census.gov>. at 301-763-6685. (SIPP Users’ Guide).

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