Document Detail


Invited commentary: positivity in practice.
MedLine Citation:
PMID:  20139125     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Positivity, or the experimental treatment assignment assumption, requires that there be both exposed and unexposed participants at every combination of the values of the observed confounders in the population under study. Positivity is essential for inference but is often overlooked in practice by epidemiologists. This issue of the Journal includes 2 articles featuring discussions related to positivity. Here the authors define positivity, distinguish between deterministic and random positivity, and discuss the 2 relevant papers in this issue. In addition, the commentators illustrate positivity in simple 2 x 2 tables, as well as detail some ways in which epidemiologists may examine their data for nonpositivity and deal with violations of positivity in practice.
Authors:
Daniel Westreich; Stephen R Cole
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Publication Detail:
Type:  Comment; Journal Article; Research Support, N.I.H., Extramural     Date:  2010-02-05
Journal Detail:
Title:  American journal of epidemiology     Volume:  171     ISSN:  1476-6256     ISO Abbreviation:  Am. J. Epidemiol.     Publication Date:  2010 Mar 
Date Detail:
Created Date:  2010-03-10     Completed Date:  2010-04-02     Revised Date:  2011-07-26    
Medline Journal Info:
Nlm Unique ID:  7910653     Medline TA:  Am J Epidemiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  674-7; discussion 678-81     Citation Subset:  IM    
Affiliation:
Department of Epidemiology, University of North Carolina, Chapel Hill, NC 27599-7435, USA. djw@unc.edu
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MeSH Terms
Descriptor/Qualifier:
Bias (Epidemiology)
Biometry / methods
Causality*
Confounding Factors (Epidemiology)*
Data Interpretation, Statistical*
Epidemiologic Methods
Humans
Propensity Score
Grant Support
ID/Acronym/Agency:
P30-AI-50410/AI/NIAID NIH HHS; R01-AA-01759/AA/NIAAA NIH HHS; T32-AI-07001/AI/NIAID NIH HHS
Comments/Corrections
Comment On:
Am J Epidemiol. 2010 Mar 15;171(6):656-63   [PMID:  20139128 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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