title: Authors' reply to Gallagher and Winocour.
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada Department of Oncology, McGill University, Montreal.
authors.forename: Laurent
authors.initials: L
authors.lastname: Azoulay
authors.affiliation: Centre for Clinical Epidemiology, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada Department of Epidemiology, Biostatistics, and Occupational Health, McGill University Division of Clinical Epidemiology, McGill University.
authors.forename: Kristian B
authors.initials: KB
authors.lastname: Filion