Downloading Older Versions of Datasets


I am interested in reproducing older results from a previous download of the 1% 1940 Decennial circa 2012. From looking at cross-tabs I suspect that IPUMS has changed the dataset (different counts of people in two states in 1940), as documented in the text I have copy-pasted from the website at the bottom of this post. However, I cannot find any documented changes to the sample person weight PERWT. Is it possible to download older editions of say, the 1% sample (including errors but also hopefully including the older person sample weights), like I can for the complete count sample?


April 30, 2013

Edited samples.

  • A new version of the 1940 1% sample is now available. The new 1940 release includes corrections as well as new data. Corrections were made to 374 person records that had been identified as living in Missouri that actually lived in Detroit, Michigan. Necessary changes were made to the relevant geographic and migration variables.
  • New geographical variables were added to the 1940 1% data that are no longer restricted by confidentiality requirements: COUNTY, METDIST, CITYMETD, URBAN and URBPOP data are now available. County, city, minor civil division, ward, tract and enumeration district information has also been added as two new sets of string variables, one that contains “clean”, standardized strings (STDCNTY, STDCITY, STDMCD, STDWARD, STDTRACT, STDED) and one that records the strings exactly as they were entered (CNTYSTR, MCDSTR, WARDSTR, INCSTR). Also for the household record, the string variable GQSTR has been added, which contains the original group quarters response as it was entered.
  • New string variables have also been entered for all but 137,588 person-level records in the 1940 1% data. The records with the missing data can be identified using the SUBS4050 variable and selecting subsamples 2 and 20. The remaining data for those two subsamples will be added in the future. The new person-level string variables are: occupation and industry (OCCSTR and INDSTR), usual occupation and industry (UOCCSTR and UINDSTR), where the respondent was living in 1935 (MST5STR, MCNY5STR and MCIT5STR), and five other demographic variables (RELSTR, BPLSTR, FBPLSTR, MBPLSTR, MTONGSTR) .

Edited variables.

  • The variable EDUC has been updated to reflect corrections by the Census to ACS 2001 and 2002 single-year files. The educational attainment question changed on the 1999 ACS questionnaire, which modified the response categories and eliminated the choice of “Vocational, technical, or business school degree.” Previously the 2001 and 2002 single-year IPUMS data dictionary incorrectly showed labels for categories 65, 71 and 82 as “1 or more years of college credit, no degree,” “2 years of college: Associate’s degree - occupational program,” and “2 years of college: Associate’s degree - academic program,” respectively. The correct data dictionary labels for categories 65, 71, and 82 are “Some college, but less than 1 year,” “1 or more years of college credit, no degree,” and “2 years of college: Associate’s degree, type not specified,” respectively.
  • For the 2007-2011 American Community Survey 5-year file the variable IND had incorrect values for the cases from 2011 due to a programming error. This error has been fixed.

I am glad you found the note about the differences in state identifiers in the sample. The following note from May 25, 2017 seems the likely source of the PERWT discrepancy you are seeing:

An improvement in data processing tools and a more sophisticated random number generator has led to altered values for some records in the variables HHWT, PERWT, and SLWT in 1940-1960 samples.

We have older versions of the samples in the IPUMS USA database, but strongly encourage users to employ the most recent version of the data as changes typically represent improvements. For more detailed questions, please email us directly (

I also want to clarify that we do not retain previous versions of the public use full count files available on IPUMS USA.

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