title: Sample size calculation for planning group sequential longitudinal trials.
abstract: Procedures are developed in this paper for sample size calculations for planning a group sequential longitudinal trial with various correlation structures, using a test statistic based on generalized estimating equations (Lee, Kim and Tsiatis) and group sequential boundaries based on type I error spending functions (Lan and DeMets).
authors.affiliation: Biostatistics Unit, Lombardi Cancer Center S112, Georgetown University Medical Center, 3800 Reservoir Road NW, Washington, D.C. 20007, USA. liua1@gunet.georgetown.edu
authors.forename: A
authors.initials: A
authors.lastname: Liu
authors.forename: J M
authors.initials: JM
authors.lastname: Boyett
authors.forename: X
authors.initials: X
authors.lastname: Xiong
mesh_terms: D000293:Adolescent; D000328:Adult; D015519:Bone Density; D002648:Child; D003627:Data Interpretation, Statistical; D002149:Energy Intake; D006801:Humans; D008137:Longitudinal Studies; D015233:Models, Statistical; D009369:Neoplasms / Q000628:therapy; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000628:therapy; D016032:Randomized Controlled Trials as Topic; D018401:Sample Size