Testing weak nulls in matched observational studies

We develop sensitivity analyses for weak nulls in matched observational studies while allowing unit-level treatment effects to vary. The methods may be applied to studies using any optimal without-replacement matching algorithm. In contrast to randomized experiments and to paired observational st...

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Main Author: Fogarty, Colin B
Other Authors: Massachusetts Institute of Technology. Operations Research Center
Format: Article
Language:English
Published: Wiley 2023
Online Access:https://hdl.handle.net/1721.1/147999
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author Fogarty, Colin B
author2 Massachusetts Institute of Technology. Operations Research Center
author_facet Massachusetts Institute of Technology. Operations Research Center
Fogarty, Colin B
author_sort Fogarty, Colin B
collection MIT
description We develop sensitivity analyses for weak nulls in matched observational studies while allowing unit-level treatment effects to vary. The methods may be applied to studies using any optimal without-replacement matching algorithm. In contrast to randomized experiments and to paired observational studies, we show for general matched designs that over a large class of test statistics, any valid sensitivity analysis for the entirety of the weak null must be unnecessarily conservative if Fisher's sharp null of no treatment effect for any individual also holds. We present a sensitivity analysis valid for the weak null, and illustrate why it is generally conservative if the sharp null holds through new connections to inverse probability weighted estimators. An alternative procedure is presented that is asymptotically sharp if treatment effects are constant, and that is valid for the weak null under additional restrictions which may be deemed benign by practitioners. Simulations demonstrate that this alternative procedure results in a valid sensitivity analysis for the weak null hypothesis under a host of reasonable data-generating processes. The procedures allow practitioners to assess robustness of estimated sample average treatment effects to hidden bias while allowing for unspecified effect heterogeneity in matched observational studies.
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spelling mit-1721.1/1479992023-02-11T03:30:45Z Testing weak nulls in matched observational studies Fogarty, Colin B Massachusetts Institute of Technology. Operations Research Center We develop sensitivity analyses for weak nulls in matched observational studies while allowing unit-level treatment effects to vary. The methods may be applied to studies using any optimal without-replacement matching algorithm. In contrast to randomized experiments and to paired observational studies, we show for general matched designs that over a large class of test statistics, any valid sensitivity analysis for the entirety of the weak null must be unnecessarily conservative if Fisher's sharp null of no treatment effect for any individual also holds. We present a sensitivity analysis valid for the weak null, and illustrate why it is generally conservative if the sharp null holds through new connections to inverse probability weighted estimators. An alternative procedure is presented that is asymptotically sharp if treatment effects are constant, and that is valid for the weak null under additional restrictions which may be deemed benign by practitioners. Simulations demonstrate that this alternative procedure results in a valid sensitivity analysis for the weak null hypothesis under a host of reasonable data-generating processes. The procedures allow practitioners to assess robustness of estimated sample average treatment effects to hidden bias while allowing for unspecified effect heterogeneity in matched observational studies. 2023-02-10T13:39:12Z 2023-02-10T13:39:12Z 2019-08-20 2023-02-10T13:31:41Z Article http://purl.org/eprint/type/JournalArticle https://hdl.handle.net/1721.1/147999 Fogarty, Colin B. 2019. "Testing weak nulls in matched observational studies." Biometrics. en 10.1111/biom.13741 Biometrics Creative Commons Attribution 4.0 International license https://creativecommons.org/licenses/by/4.0/ application/pdf Wiley Wiley
spellingShingle Fogarty, Colin B
Testing weak nulls in matched observational studies
title Testing weak nulls in matched observational studies
title_full Testing weak nulls in matched observational studies
title_fullStr Testing weak nulls in matched observational studies
title_full_unstemmed Testing weak nulls in matched observational studies
title_short Testing weak nulls in matched observational studies
title_sort testing weak nulls in matched observational studies
url https://hdl.handle.net/1721.1/147999
work_keys_str_mv AT fogartycolinb testingweaknullsinmatchedobservationalstudies