# ASEC vs. Census CPS numbers

**URL:** <https://forum.ipums.org/t/asec-vs-census-cps-numbers/4286>\
**Category:** CPS\
**Created:** [August 24, 2021, 9:19pm UTC](https://forum.ipums.org/t/asec-vs-census-cps-numbers/4286 "2021-08-24T21:19:57Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Moya\_Chin](https://avatars.discourse-cdn.com/v4/letter/m/3d9bf3/32.png) [@Moya\_Chin](https://forum.ipums.org/u/Moya_Chin)\
**Post date:** [August 24, 2021, 9:19pm UTC](https://forum.ipums.org/t/asec-vs-census-cps-numbers/4286/1 "2021-08-24T21:19:58Z")

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I’m having some issues replicating the Census CPS numbers using the IPUMS ASEC samples. I’m using [this report](https://www.census.gov/content/dam/Census/library/publications/2020/demo/p60-270.pdf), see pg. 35-36 “All Races”.

For example, if I do a simple comparison of the number of observations, for 2005, the number of households is 114,384 thousand. Using the 2005 IPUMS ASEC, if I keep 1 observation per household and sum up the ASECWTH/1000, I get 113,475,724 which does not match exactly.

Am I using the weights incorrectly, or is there a reason for this discrepancy?

Edit: I have also come across some negative ASEC weights. These have come up in the 1969 files (unsure about others) see SERIAL == 2467 or 3397 or 22990. I was reading in the .dat file manually, so possible that it has been read in incorrectly but I think this is unlikely.

Thanks!

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**Author:** ![Grace\_Cooper](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/grace_cooper/32/376_2.png) [@Grace\_Cooper](https://forum.ipums.org/u/Grace_Cooper)\
**Post date:** [September 2, 2021, 6:31pm UTC](https://forum.ipums.org/t/asec-vs-census-cps-numbers/4286/2 "2021-09-02T18:31:41Z")

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According to [Income and Poverty in the United States: 2019](https://www.census.gov/content/dam/Census/library/publications/2020/demo/p60-270.pdf) (the report that you linked to), the numbers are based on the number of households as of March of the following year (see the sub-heading at the top of page 35 of the pdf). To check that this solves your problem, I compared the number of households in the 2006 IPUMS CPS ASEC (114,510,050) with the number of households in 2005 according to the above-mentioned CPS report (114,384,000), which is a much closer match.