title: On the Existence of Constant Accrual Rates in Clinical Trials and Direction for Future Research.
abstract: Many clinical trials fall short of their accrual goals. This can be avoided with accurate accrual prediction tools. Past researchers provide important methodological alternative models for predicting accrual in clinical trials. One model allows for slow accrual at the start of the study, which eventually reaches a threshold. A simpler model assumes a constant rate of accrual. A comparison has been attempted but we wish to point out some important considerations when comparing these two models. In fact, we can examine the reasonableness of a constant accrual assumption (simpler model) which had data 239 days into a three-year study. We can now update that and report accumulated from the full three years of accrual data and we can demonstrate that constant accrual rate assumption was met in this particular study. We will use this report to frame future research in the area of accrual prediction.
authors.affiliation: Department of Biostatistics, The University of Kansas Medical Center, Kansas City, USA.
authors.forename: Byron J
authors.initials: BJ
authors.lastname: Gajewski
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Simon
authors.forename: Susan E
authors.initials: SE
authors.lastname: Carlson
keywords: Bayesian; exponential; inverse gamma; prior elicitation; sample size