title: Population versus individual level causal effects.
authors: Department of Sociology, Harvard University, Cambridge, MA 02138, USA. elwert@fas.harvard.edu
authors: Felix
authors: F
authors: Elwert
authors: Christopher
authors: C
authors: Winship
mesh_terms: D015984:Causality; D006801:Humans; D012907:Smoking / Q000453:epidemiology