U.S. Census Bureau


Survey of Income and Program Participation (SIPP) data

The concepts used in the SIPP and the March supplement to the Current Population Survey (CPS) differ in some regards. These differences occur primarily between components of the income definition used in each survey and the manner in which certain reference units are categorized. An explanation of these differences follows.

Two basic units of reference common to both the SIPP and CPS are people and households. Groups of people living together, when combined based on relationship, form family units. A family refers to a group of two or more people related by birth, marriage, or adoption who reside together (one of whom is the householder). Two or more people who live together and are related to one another, but not related to the householder, form an unrelated subfamily. People in unrelated subfamilies are not included in the count of family members in the CPS, but are included as family members for the SIPP.

A unique feature of a longitudinal survey, such as SIPP, is its ability to capture change over time. A cross-sectional survey, such as CPS, does not have this feature and can only provide a series of snapshots of the socio-economic conditions that exist at different fixed points in time. CPS data are based on the demographic characteristics as they existed at the time the survey was conducted and are applied to the economic characteristics that existed for the previous calendar year. The demographic data in the SIPP are collected with the economic data throughout the calendar year and are likely to have changed during the year. In order to incorporate the effect of changes over time in family compositions in measures of SIPP income data, the data are presented for people rather than families. People are characterized by the income of their respective family unit based on living arrangements each month during the calendar year.

The definition of income used in the SIPP is basically the same as in the CPS. It reflects money income before taxes and does not include the value of noncash benefits such as employer-provided health insurance, food stamps, or medicaid. Differences do exist however, they are:

For an overview of the SIPP and a detailed explanation of the concepts used in that survey, see Current Population Reports, Series P70, No. 24, Transitions in Income and Poverty Status: 1987-88.

Bureau of Economic Analysis (BEA) personal income series

The income data presented in CPS reports are not directly comparable with estimates of aggregate personal income prepared by the Bureau of Economic Analysis, Department of Commerce, nor with the distributions of families and unrelated individuals by family personal income brackets published by that Bureau between the years 1929 to 1963. The lack of correspondence stems from the following differences in definition and coverage:

  1. Income definition. The table below shows an overview of the income sources included in the BEA Personal Income Series and the Census Bureau Money Income Series.

    Table 1. Overview of Income Concepts:

    National Income and Product Accounts Personal Income and Household Survey Money Income


    Sources of Income In Both

    Personal Income and Money Income


    In Personal Income

    but not Money Income

    In Money Income

    but not Personal Income



    employer-provided food and lodging


    Farm and nonfarm
    capital consumption adjustments
    inventory valuation adjustment
    construction adjustment
    defaulter's gain and bad debt expense
    income of cooperatives
    farm products consumed on farm
    change in farm inventories
    interest received by farm corporations

    patronage dividends from
    farm cooperatives



    interest on life insurance
    interest on private pension plans
    value of free financial services
    interest received by fiduciaries and nonprofits
    unredeemed interest on US savings bonds



    IRA and Keogh dividends
    dividends received by fiduciaries and nonprofits
    small business corporation income


    Rent and royalties

    rental value of owner-occupied housing
    rent received by fiduciaries and nonprofits
    capital consumption adjustment


    Social Security and Railroad Retirement



    Federal and state Supplemental Security Income



    Family assistance

    adoption assistance


    Other cash welfare



    Federal and state unemployment compensation

    employer contributions to private supplemental unemployment compensation funds benefits from private
    supplemental unemployment compensation funds /2


    Federal and state worker's compensation

    employer contributions to private worker=s compensation funds

    benefits from private worker's compensation funds /2


    Veterans= benefits



    [Private pensions] /1

    employer contributions to private pension and profit-sharing funds

    benefits from private pension and profit-sharing funds /2


    Federal employee pensions



    Military retirement



    State and local government employee pensions



    Estates and trusts



    Education assistance



    Foster child care payments




    federal hospital and medical insurance benefits

    cash benefits from accident and disability insurance


    state public assistance medical care

    state temporary sickness or disability insurance payments

    pension benefit guaranty


    payments from annuities and paid-up life insurance


    food stamps

    draw or regular payments from IRA or Keogh


    direct relief

    child support


    earned income tax credit



    energy assistance

    assistance from friends and relatives


    business transfer payments to persons

    other cash income


    lump sum payments

    personal contributions to social insurance

    /1 The Personal Income and Money Income concepts of private pensions are mutually exclusive. The same is true of government pensions following the 1999 comprehensive revision of the NIPAs.

    /2 These items are not part of Personal Income but do appear elsewhere in the NIPAs.


  3. Source of data. The personal income series is estimated largely on the basis of data derived from business and governmental sources. These sources include the industrial and population censuses, employer's wage reports under the Social Security programs, and records of disbursements to individuals by governmental agencies. The income data presented in the census reports, on the other hand are based directly on field surveys of households.
  4. Income data obtained in household interviews are subject to various types of reporting errors which tend to produce an understatement of income. For more information on this subject, see Current Population Reports, Series P60-206, Appendix E, which may be accessed on the internet at http://www.census.gov/hhes/www/income/income98.html. It is estimated that the income surveys conducted by the Census Bureau during the past few years have obtained about 89 percent of the comparable total money income aggregates and about 99 percent of the comparable money wage or salary aggregates derived from the personal income series prepared by BEA.

    For a more detailed discussion of the differences between distributions using Census money income and BEA personal income, see Size Distribution of Family Personal Income: Methodology and Estimates for 1964, by Edward C. Budd, Daniel B. Radner, and John C. Hinrichs, Bureau of Economic Analysis, BEA-SP 7321, June 1973.

  5. Population coverage. The table below shows the differences between the population universes for the Census Bureau Money Income Series and BEA=s Personal Income Series.

    Table 2. Overview of Population Universes: Bureau of Economic Analysis Personal Income and Census Bureau Money Income

    Populations Covered in Both Personal Income and Money Income

    In Personal Income but not Money Income

    In Money Income but not Personal Income

    Civilian noninstitutionalized

    military on US post without family

    foreign professional and migratory workers



  7. Average Income. The average income figures (e.g., for geographical regions) represent income per capita, i.e., they were derived by dividing total income by the total population including men, women, and children. Most of the Census averages, in contrast, are for households, families, unrelated individuals, or income recipients 15 years old and over.


Department of Agriculture Farm Income Series

The farm income data are not directly comparable to that published by the U.S. Department of Agriculture (USDA) for several reasons. The USDA publishes two major series on income of farms: (1) net farm income and (2) net cash farm income.

For reasons listed below, the estimates of farm self-employment income per person or per family as published by the Census Bureau differ from estimates of operators' net farm income or net cash farm income per farm as published by the Department of Agriculture:

  1. The unit of analysis in the USDA estimates is an establishment (farm ) rather than a household as in the Census Bureau estimate.
  2. The estimates of farm self-employment income as published by the Census Bureau and USDA's net cash income series exclude the nonmoney income items of crops grown for home consumption and an imputed rental value for farm dwellings. However, these are included in the estimates of operators' net farm income per farm.
  3. The USDA estimate of net farm income includes the value of the change in inventories of commodities from the beginning to the end of the year. The USDA net cash farm income and the Census Bureau farm self-employment income do not.
  4. The USDA series include the net income of farm operators from the rental of farms to other farmers but the census definition classifies these receipts as income other than earnings, not income from farm self-employment.
  5. The USDA series is based on income from farms which are organized as proprietorships, partnerships, and corporations. The Census Bureau excludes corporate farm income. (The Bureau of Economic Analysis does estimate the proportions of the USDA estimate which are earned by corporate and noncorporate farms for inclusion in the national Income and Product Account.)

The estimates of the USDA differ from the estimates of the Census Bureau methodologically as well as conceptually. The USDA estimates are based on data derived from the Census of Agriculture, farm surveys, business, and governmental sources, and are not available at a farm or household level, while the Census Bureau estimates are compiled from data collected in sample surveys. The latter estimates are subject not only to sampling variation but also to errors of response and nonreporting.

For a more detailed discussion of the concepts and methodology used in the USDA estimates, see U.S. Department of Agriculture Handbook No. 365, Major Statistical Series of the U.S. Department of Agriculture, Vol. 3, Gross and Net Farm Income, September 1969.


Federal Income Tax Data

For several reasons, the income data published by the Census Bureau are not directly comparable with those which may be obtained from statistical summaries of income tax returns. Income, as defined for tax purposes, differs somewhat from the concept used by the Census Bureau. For example, certain types of receipts, such as veterans' payments, SSI, and TANF (formerly known as AFDC), are not reported on Federal tax returns. Moreover, the coverage of income tax statistics is less inclusive because many people with low incomes are not required to file tax returns. Furthermore, some income tax returns are filed as separate returns and others as joint returns; consequently, the income reporting unit is not consistently either a family or a person.

Old-Age, Survivors', Disability, and Health Insurance earnings record data. Data shown in Census Bureau reports and the distributions made upon the basis of Old-Age, survivors', Disability, and Health Insurance earnings record data differ for the reasons listed below.

  1. The earnings of the following groups are not covered by the earnings record data: many Federal, State, and local government employees, some employees of nonprofit organizations, workers covered by the Railroad Retirement Act, and people who are not covered by the program because of insufficient earnings, including some farm and nonfarm self-employed people, some farm workers, and domestic servants.
  2. Employees' earnings in excess of $51,300 per employer are not covered by the earnings record data.
  3. Income other than earnings is not covered by the earnings record data.
  4. The earnings record data are based upon employers' Social Security tax reports and the Federal income tax returns of self-employed people, while the data presented in this report are obtained by household interviews.


The wording in this document is revised from that published in P60, No. 184. We updated this section to replace passive voice with active voice; replaced "persons" with "people"; "Bureau of the Census" with "Census Bureau"; and changed "AFDC" to "TANF".

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Source: U.S. Census Bureau, Housing and Household Economic Statistics Division