title: Baseline observation carry forward: reasoning, properties, and practical issues.
abstract: In some longitudinal drug studies, regulatory agencies suggest baseline observation carry forward (BOCF) as a method of handling patient dropout, despite the existence of many criticisms to BOCF. The reason for using BOCF is not clear to many users who either treat BOCF as an imputation method or consider BOCF to be "conservative" in the sense that it allows treatment effect to be evaluated with a severe penalty for dropouts. In this article we address the following questions and issues: What is the reason for using BOCF? Is BOCF a conservative approach to assessing drug efficacy? Is BOCF reasonable? If not, what are the alternatives? Our discussions are based on both theoretical and practical viewpoints.
authors.affiliation: Department of Statistics, University of Wisconsin, Madison, Wisconsin 53706, USA. shao@cs.wisc.edu
authors.forename: Jun
authors.initials: J
authors.lastname: Shao
authors.forename: David C
authors.initials: DC
authors.lastname: Jordan
authors.forename: Yili L
authors.initials: YL
authors.lastname: Pritchett
mesh_terms: D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D003627:Data Interpretation, Statistical; D006801:Humans; D008137:Longitudinal Studies; D015233:Models, Statistical; D010352:Patient Dropouts; D015990:Placebo Effect; D012107:Research Design / Q000706:statistics & numerical data*; D013997:Time Factors; D016896:Treatment Outcome