Weighting

For all CPS data files a single weight is prepared and used to compute the monthly labor force status estimates. An additional weight was prepared for the earnings universe which roughly corresponds to wage and salary workers in the two outgoing rotations. This is explained below in the section on earnings data. However, the difference in content of the March CPS supplement requires the presentation of additional weights: a household weight, a family weight, and a March supplement weight. In this section we briefly describe the construction and use of these weights. Chapter 5 of Technical paper 40, The Current Population Survey: Design and Methodology provides documentation of the weighting procedures for the CPS both with and without supplement questions.

The final weight, which is the product of several adjustments, is used to produce population estimates for the various items covered in the regular monthly CPS. This weight is constructed from the basic weight for each person, which represents the probability of selection for the survey. The basic weight is adjusted for special sampling situations and failure to obtain interviews from eligible households (noninterview adjustment). A two-stage ratio estimation procedure adjusts the sample population to the known distribution of the entire population. This two-stage ratio estimation process produces factors which are applied to the basic weight (after the special weighting and noninterview adjustments are made) and results in the final weight associated with each record. In summary, the final weight is the product of: (1) the basic weight, (2) adjustments for special weighting, (3) noninterview adjustment, (4) first stage ratio adjustment factor, and (5) second stage ratio adjustment factor. This final weight should be used when producing estimates from the basic CPS data.

Differences in the questionnaire, sample and data uses for the March CPS supplement result in the need for additional adjustment procedures to produce what is called the March supplement weight. The sample for the March CPS supplement is expanded to include members of the Armed Forces who are living in civilian housing or with the family on a military base, as well as additional Hispanic households which are not included in the monthly labor force estimates.

The expanded sample and the need to have a husband and wife receive the same weight has resulted in a weighting system which produces the March supplement weight. The March supplement weight should be used for producing estimates from March supplement data.

Finally, household and family weights are the weights assigned from the householder or reference person after all adjustments have been made and should be used when tabulating estimates of families-households.

Earnings Data

Beginning in 1982, usual hourly and weekly earnings data appear on the Annual Demographic File (ADF) for that portion of the population roughly corresponding to wage and salary workers (self-employed persons in incorporated businesses are excluded, although they are normally included with the wage and salary population). These data are now collected on a monthly basis in the two outgoing rotation groups as part of the basic CPS labor force interview.

Since the intent of the regular collection of earnings data was to initiate a family earnings data series, all persons in the two outgoing rotations receive an ``earnings weight,'' even if they are not eligible for the earnings item. The earnings weight is a simple ratio-estimation to the person's labor force status by age, race, and sex. When tabulating estimates of earnings based on basic CPS data, use the earnings weight.

Further information on this earnings series is contained in Technical Description of the Quarterly Data on Weekly Earnings from the Current Population Survey, BLS Report #601, July 1980. This report is available on request from the U.S. Department of Labor, Bureau of Labor Statistics, Washington, D.C. 20212. Attn: Office of Inquiries and Correspondence.

NOTE: For 1982 and 1983, usual weekly earnings are not present for individuals who were not paid on an hourly basis.

Annual Demographic Survey (March 1996 CPS) Sampling and Weighting Page

CPS Main Page