Pub. date: 2008 | Online Pub. Date: November 27, 2007 | DOI: 10.4135/9781412953948 | Print ISBN: 9781412928168 | Online ISBN: 9781412953948| Publisher:SAGE Publications, Inc.About this encyclopedia
William D. Shannon
Propensity score adjustment is a method of adjusting for all covariates in an observational case-control study, using scalar matching. In case-control studies, the goal is typically to determine if one group (cases) of subjects has a different outcome than another group (controls). These groups might be defined by which treatment they received or which factor they were exposed to, and the purpose of the study is to determine if the treatments or factors result in different outcomes in the cases than in the controls. For example, we can observe people who smoke (cases) and people who don't smoke (controls) and compare the rates of cancer between the two groups. Because people cannot ethically be assigned to one or the other condition (smoking or nonsmoking) we have to accept the groupings that exist. However, because random assignment to condition was not used, the two groups very likely differ on other factors, ...