# ASEC

**URL:** <https://forum.ipums.org/t/asec/1545>\
**Category:** CPS\
**Created:** [January 20, 2017, 4:38am UTC](https://forum.ipums.org/t/asec/1545 "2017-01-20T04:38:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Cassie](https://avatars.discourse-cdn.com/v4/letter/c/db5fbb/32.png) [@Cassie](https://forum.ipums.org/u/Cassie)\
**Post date:** [January 20, 2017, 4:38am UTC](https://forum.ipums.org/t/asec/1545/1 "2017-01-20T04:38:00Z")

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What’s the unique id for me to identify household if I want to merge ASEC data along the time.

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**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:** [January 20, 2017, 3:24pm UTC](https://forum.ipums.org/t/asec/1545/2 "2017-01-20T15:24:00Z")

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A unique id, for purposes of linking households between ASEC samples, can be created by combining [HRHHID](https://cps.ipums.org/cps-action/variables/HRHHID#description_section) and [HRHHID2](https://cps.ipums.org/cps-action/variables/HRHHID2#codes_section). Note that your match rate will be under fifty-percent for any given two-year period. This is because only half of the sample is [eligible](https://cps.ipums.org/cps/sample_designs.shtml) to appear in both years of any two consecutive years. Also, households and persons can drop out of the survey (due to relocation, refusing to participate, etc.).