I am trying to replicate BLS estimates of employment and labor force participation levels. Starting in 1998, I have been able to do this successfully using PWCMPWGT as stored in the files available from the NBER and Census Bureau.
Before 1998, however, I cannot exactly reproduce the official estimates shown here using any publicly available weights. If I use, for example, the IPUMS CPS SDA tool with YEAR(1995),MONTH(9),AGE(16-99) and the WTFINL weight, I get the civilian labor force level as 132,371 (thousands) whereas the official number is 132,341. This calculation does, however, give exactly the official civilian noninstitutional population of 199,005.
Is it possible to replicate these BLS statistics at all, using IPUMS or any other publicly available microdata?
I can confirm that I’m seeing this same small discrepancy in labor force estimates when using WTFINL, but I was unable to determine the source of this discrepancy. I checked that we have correctly coded respondents based on the data provided in the Census Bureau Public Use Microdata Sample (PUMS) and that the data matches the monthly files shared by the NBER. Moreover, the 1995 CPS ASEC codebook states that “for all CPS data files a single weight is prepared and used to compute the monthly labor force status estimates.” Based on this documentation, I would expect you to be able to replicate these estimates using WTFINL. The two-step composite estimation method for COMPWT was introduced in January 1998, which is why this weight is not available for earlier samples.
It is possible that the FRED estimates are derived from a different version of the microdata or they recode labor force participation using a different definition than the one presented in the PUMS. However, without more knowledge of the methodology from the linked FRED data, it’s difficult to tell what the cause of this discrepancy might be. This annual time series from FRED provides a detailed definition of the employed and unemployed population. You might compare the definition used there with the original ASEC codebook to note any potential discrepancies. You can also explore the original versions of the employment/labor force variables that we make available as unharmonized variables. These can be found using the search tool by checking the “include unharmonized variables” option or by using the drop-down menu in the variable selection screen after filling the unharmonized variables bubble. Some of the relevant variables include UH_MLR_B3 (monthly labor force recode), UH_ANYWK_B2 (any work at all last week), UH_LK_B1 (look for work last 4 weeks), UH_LAYOFF_B1 (on layoff last week), and UH_LKAVR_B1 (reason could not start a job last week if offered one).