# CEPR CPS & IPUMS CPS - Merge & differences in sample size?

**URL:** <https://forum.ipums.org/t/cepr-cps-ipums-cps-merge-differences-in-sample-size/3895>\
**Category:** CPS\
**Created:** [December 15, 2020, 11:13am UTC](https://forum.ipums.org/t/cepr-cps-ipums-cps-merge-differences-in-sample-size/3895 "2020-12-15T11:13:13Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Johannes\_Mueller](https://avatars.discourse-cdn.com/v4/letter/j/ed655f/32.png) [@Johannes\_Mueller](https://forum.ipums.org/u/Johannes_Mueller)\
**Post date:** [December 15, 2020, 11:13am UTC](https://forum.ipums.org/t/cepr-cps-ipums-cps-merge-differences-in-sample-size/3895/1 "2020-12-15T11:13:13Z")

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Dear all,

I am a bit puzzled by two questions:

1. Can the CEPR CPS and the IPUMS CPS be merged (specifically, 1990 - 2019 March files)
2. Do the CEPR CPS and the IPUMS CPS March files differ in sample size? If so, why is that the case?

Thank you very much in advance!

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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:** [December 22, 2020, 9:36pm UTC](https://forum.ipums.org/t/cepr-cps-ipums-cps-merge-differences-in-sample-size/3895/2 "2020-12-22T21:36:30Z")

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Both the basic monthly and ASEC (March) files from [CEPR CPS](http://ceprdata.org/cps-uniform-data-extracts/cps-outgoing-rotation-group/cps-org-data/) and [IPUMS CPS](https://cps.ipums.org/cps/index.shtml) have the same sample size and can be merged on a 1:1 basis. I found it useful to merge on the following IPUMS variables: MONTH, STATEFIP, HRHHID, HRHHID2, SEX, AGE, and PERNUM. For a more detailed discussion on merging CEPR CPS with IPUMS CPS, see this [forum post](https://forum.ipums.org/t/merge-cepr-cps-org-data-and-ipums-cps/2672).

I hope this helps.