title: Immortal time bias. Response to: Achinger, Go and Ayus.
authors.affiliation: Department of Epidemiology, Biostatistics and Occupational Health, McGill University, 1020 Pine Ave. West, Montreal, PQ, H3A 1A2, Canada. E-mail: james.hanley@mcgill.ca.
authors.forename: James A
authors.initials: JA
authors.lastname: Hanley
mesh_terms: D000818:Animals; D015982:Bias; D006801:Humans; D013997:Time Factors