# merge

**URL:** <https://forum.ipums.org/t/merge/731>\
**Category:** General\
**Created:** [December 8, 2014, 10:34pm UTC](https://forum.ipums.org/t/merge/731 "2014-12-08T22:34:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![hw227](https://avatars.discourse-cdn.com/v4/letter/h/43a26b/32.png) [@hw227](https://forum.ipums.org/u/hw227)\
**Post date:** [December 8, 2014, 10:34pm UTC](https://forum.ipums.org/t/merge/731/1 "2014-12-08T22:34:00Z")

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Hello,

I tried to merge the 1974 NHIS file for the hypertension supplement (hyperten) with the IHIS data (which include the full sample from 1963-2013) but no respondent was matched.

Please help.

Thanks very much in advance!

Hua

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**Author:** ![Tim\_Moreland](https://avatars.discourse-cdn.com/v4/letter/t/f1d935/32.png) [@Tim\_Moreland](https://forum.ipums.org/u/Tim_Moreland)\
**Post date:** [December 10, 2014, 6:43pm UTC](https://forum.ipums.org/t/merge/731/2 "2014-12-10T18:43:00Z")

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First, I would refer you to the [Hypertension variables](https://www.ihis.us/ihis-action/variables/group?id=conditions_hypertension) already available in the IHIS data, which includes variables from the 1974 Hypertension supplement.

If you are still interested in merging, you should refer to the [User Note](https://www.ihis.us/ihis/userNotes_links.shtml) on linking IHIS and NHIS datasets. You will want to merge person records by using the [NHISPID](https://www.ihis.us/ihis-action/variables/NHISPID#description_section) linking key in the IHIS dataset and the person-level unique identifiers in the NHIS supplement dataset: quarter, psunumr, weekcen, segnum, hhnum, and pnum.

Hope this helps.