# Which was the first 1980 US Census 1% sample on IPUMS USA? **URL:** \ **Category:** USA\ **Created:** [April 16, 2018, 6:41pm UTC](https://forum.ipums.org/t/which-was-the-first-1980-us-census-1-sample-on-ipums-usa/2289 "2018-04-16T18:41:00Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![rcragun](https://avatars.discourse-cdn.com/v4/letter/r/71e660/32.png) [@rcragun](https://forum.ipums.org/u/rcragun)\ **Post date:** [April 16, 2018, 6:41pm UTC](https://forum.ipums.org/t/which-was-the-first-1980-us-census-1-sample-on-ipums-usa/2289/1 "2018-04-16T18:41:00Z")
Which was the first 1980 US Census 1% sample available on IPUMS USA, and has that sample been changed since 2001 by either changing which observations are in the sample or by adding in preiviously-missing data (not entirely new variables) for any obervations? I am trying to replicate results from a published paper, and there is a 1039-person difference in the sample sizes we end up with (which the author cannot explain). ---
**Author:** ![JeffBloem](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/jeffbloem/32/40_2.png) [@JeffBloem](https://forum.ipums.org/u/JeffBloem)\ **Post date:** [April 16, 2018, 7:46pm UTC](https://forum.ipums.org/t/which-was-the-first-1980-us-census-1-sample-on-ipums-usa/2289/2 "2018-04-16T19:46:00Z")
Much of this information, if available, is documented on the [revisions page](https://usa.ipums.org/usa-action/revisions). Specifically, the 1980 Labor market Areas sample and the 1980 Detailed Metro/Nonmetro sample were both released on November 23, 2004. It looks like the 1980 Metro sample and the 1980 Urban/rural sample were both available before that time. So it seems like the paper could have used either of these latter two samples. Since then there have been a number of changes and additions to variables within these samples. I’d suggest looking through these changes to verify if any of these fixes may be influencing your sample size.