Abstract Theory and simulations show that variables affecting the outcome only through exposure, known as instrumental variables (IVs), should be excluded from propensity score (PS) models. In pharmacoepidemiologic studies based on automated healthcare databases, researchers will sometimes use a...

Abstract One widely used control chart, the -chart, is based on the assumption that means of samples drawn from the process are normally distributed. When the normality assumption is not valid, control chart users may choose from several different courses of action. These include using Box-Cox...

Biographical note: EpsteinJoshua M.: Joshua M. Epstein is a Senior Fellow in Economic Studies at the Brookings Institution, a founding member of the Brookings-Johns Hopkins Center on Social and Economic Dynamics, and a member of the External Faculty of the Santa Fe Institute. He is the coauthor...