# For the variable BMI, why are 65% of cases not in universe for the combined 2000-2013 IHIS?

**URL:** <https://forum.ipums.org/t/for-the-variable-bmi-why-are-65-of-cases-not-in-universe-for-the-combined-2000-2013-ihis/916>\
**Category:** HEALTH SURVEYS\
**Created:** [June 9, 2015, 7:23pm UTC](https://forum.ipums.org/t/for-the-variable-bmi-why-are-65-of-cases-not-in-universe-for-the-combined-2000-2013-ihis/916 "2015-06-09T19:23:00Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![keithvm](https://avatars.discourse-cdn.com/v4/letter/k/e0b2c6/32.png) [@keithvm](https://forum.ipums.org/u/keithvm)\
**Post date:** [June 9, 2015, 7:23pm UTC](https://forum.ipums.org/t/for-the-variable-bmi-why-are-65-of-cases-not-in-universe-for-the-combined-2000-2013-ihis/916/1 "2015-06-09T19:23:00Z")

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For the variable BMI, why are 65% of cases not in universe for the combined 2000-2013 IHIS? This seems unusually high for top and bottom coding to protect confidentiality.

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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 10, 2015, 6:55pm UTC](https://forum.ipums.org/t/for-the-variable-bmi-why-are-65-of-cases-not-in-universe-for-the-combined-2000-2013-ihis/916/2 "2015-06-10T18:55:00Z")

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As noted in the [BMI variable’s Universe Tab](https://www.ihis.us/ihis-action/variables/BMI#universe_section), from 2000-2013 only sample adults were include in the BMI question universe. You can identify sample adults with the [ASTATFLG](https://www.ihis.us/ihis-action/variables/ASTATFLG#codes_section) variable. In order to generate nationally representative estimates from sample adult variables you will need to use the [SAMPWT](https://www.ihis.us/ihis-action/variables/SAMPWEIGHT#description_section) weight variable.

I hope this helps.