# About the observational category

**URL:** <https://discourse.datamethods.org/t/about-the-observational-category/31>\
**Category:** observational\
**Tags:** tx-compare, observational\
**Created:** [July 14, 2018, 3:04pm UTC](https://discourse.datamethods.org/t/about-the-observational-category/31 "2018-07-14T15:04:00Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![f2harrell](https://discourse.datamethods.org/user_avatar/discourse.datamethods.org/f2harrell/32/165_2.png) [@f2harrell](https://discourse.datamethods.org/u/f2harrell)\
**Post date:** [July 14, 2018, 3:04pm UTC](https://discourse.datamethods.org/t/about-the-observational-category/31/1 "2018-07-14T15:04:00Z")

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Methods for comparison of nonrandomized treatments, including propensity score and instrumental variables approaches