5 papers · 1 filter
Factorial clinical trials in the presence and absence of plausible statistical interactions between treatment factors. A historical review of the methodological literature
Rebecca E. A. Walwyn, Pritaporn Kingkaew, Alan A. Montgomery +2
Factorial trials can be conducted when statistical interactions between two or more treatment factors are not anticipated, but also when they are. A k-in-1 factorial trial answers…
Orthogonal factorial designs for trials of therapist-delivered interventions: Randomising intervention-therapist combinations to patients
Rebecca EA Walwyn, Rosemary A Bailey, Arpan Singh +2
It is recognised that treatment-related clustering should be allowed for in the sample size and analyses of individually-randomised parallel-group trials that evaluate therapist-de…
Sample size calculations for multilevel factorial longitudinal cluster randomised trials
Rhys Bowden, Rebecca Walwyn, Jessica Kasza +4
Typically, trials investigate the impact of either an individual-level intervention on participant outcomes, or the impact of a cluster-level intervention on participant outcomes.…
Efficient and flexible simulation-based sample size determination for clinical trials with multiple design parameters
Duncan T. Wilson, Rebecca E. A. Walwyn, Richard Hooper +2
Simulation offers a simple and flexible way to estimate the power of a clinical trial when analytic formulae are not available. The computational burden of using simulation has, ho…
Bayesian design and analysis of external pilot trials for complex interventions
Duncan T. Wilson, James M. S. Wason, Julia Brown +2
External pilot trials of complex interventions are used to help determine if and how a confirmatory trial should be undertaken, providing estimates of parameters such as recruitmen…