title: A note on the small sample behavior of logistic regression in a bioassay setting.
abstract: The logistic regression procedure is a popular statistical method used when analyzing quantal dose-response data. However, logistic regression results based on a poorly designed experiment can be seriously compromised. Our results indicate that depending on the spacing of the doses, the number of doses, and the number of replications at each dose, the user can get very misleading results, including ineffective lack-of-fit tests and severely biased coefficient estimates along with biased estimates of response. In addition, variance formulas based on asymptotic theory may be completely inappropriate. Simulation results are used to support these statements.
authors.affiliation: Department of Management Science and Information Technology, Virginia Polytechnic Institute and State University, Blacksburg 24061, USA.
authors.forename: Q J
authors.initials: QJ
authors.lastname: Nottingham
authors.forename: J B
authors.initials: JB
authors.lastname: Birch
mesh_terms: D004305:Dose-Response Relationship, Drug; D016015:Logistic Models