Hsu, Jesse Y.; Small, Dylan S.; Rosenbaum, Paul R. - In: Journal of the American Statistical Association 108 (2013) 501, pp. 135-148
In an observational study of treatment effects, subjects are not randomly assigned to treatment or control, so differing outcomes in treated and control groups may reflect a bias from nonrandom assignment rather than a treatment effect. After adjusting for measured pretreatment covariates,...
