# Can I combine the 5% 1980 US Census with 1% 1980 US Cenus?

**URL:** <https://forum.ipums.org/t/can-i-combine-the-5-1980-us-census-with-1-1980-us-cenus/566>\
**Category:** USA\
**Created:** [June 20, 2014, 11:04pm UTC](https://forum.ipums.org/t/can-i-combine-the-5-1980-us-census-with-1-1980-us-cenus/566 "2014-06-20T23:04:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Joyful](https://avatars.discourse-cdn.com/v4/letter/j/d2c977/32.png) [@Joyful](https://forum.ipums.org/u/Joyful)\
**Post date:** [June 20, 2014, 11:04pm UTC](https://forum.ipums.org/t/can-i-combine-the-5-1980-us-census-with-1-1980-us-cenus/566/1 "2014-06-20T23:04:00Z")

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Can I combine the 5% 1980 US Census with 1% 1980 US Cenus? The weights would be adjusted with perwt\*5/6 etc.

Earlier posts said we can do this for 1970 Census. But 1980 Census is a 5% sample, would “sample overlap” become too big an issue that we are not supposed to merge a 5% with a 1% sample?

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**Author:** ![grover](https://sea1.discourse-cdn.com/flex019/user_avatar/forum.ipums.org/grover/32/5_2.png) [@grover](https://forum.ipums.org/u/grover)\
**Post date:** [June 23, 2014, 3:46pm UTC](https://forum.ipums.org/t/can-i-combine-the-5-1980-us-census-with-1-1980-us-cenus/566/2 "2014-06-23T15:46:00Z")

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According to the “Selection of the Public-Use-Microdata Samples” section of the [1980 Sample Design page](https://usa.ipums.org/usa/voliii/1980samp.shtml), the procedure for selecting the microdata samples was designed to, “minimize the likelihood that any one case would be selected into more than one public-use microdata sample, and the overlap among the samples may be considered negligible.” So combining the samples should not be problematic.

I hope this helps.