title: Statistics in nonrandomized studies.
authors.forename: K J
authors.initials: KJ
authors.lastname: Rothman
mesh_terms: D015984:Causality; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D015986:Confounding Factors, Epidemiologic; D004812:Epidemiologic Methods; D011897:Random Allocation