Related Experiment Video
Updated: Jun 23, 2026

Repeated Transcranial Magnetic Stimulation Combined with Action Observation Training in Children with Spastic Cerebral Palsy
Published on: August 9, 2024
How do multi-stage, multi-arm trials compare to the traditional two-arm parallel group design--a reanalysis of 4
F M-S Barthel1, M K B Parmar, P Royston
1Department of Biostatistics, Institute of Psychiatry, King's College London, London, UK. sophie@fm-sbarthel.de
Background:
To speed up the evaluation of new therapies, the multi-arm, multi-stage trial design was suggested previously by the authors.
Methods:
In this paper, we evaluate the performance of the two-stage, multi-arm design using four cancer trials conducted at the MRC CTU. The performance of the design at fictitious interim analyses is assessed using a conditional bootstrap approach.
Results:
Two main aims are addressed: the error rate of correctly carrying on/stopping the trial at an interim analysis as well as quantifying the gains in terms of resources by employing this design. Furthermore, we make suggestions for the best timing of this interim analysis.
Conclusion:
Multi-arm, multi-stage trials are an effective way of speeding up the therapy evaluation process. The design performs well in terms of the type I and II error rates.
Related Concept Videos
Bioequivalence Experimental Study Designs: Repeated Measures, Cross-Over, Carry-Over, and Latin Square Designs
Crossover Experiments
Crossover designs are performed even with smaller sample sizes since the samples can act as their controls. These are better than simple randomized trials since patients are exposed to all the treatments.
Group Design
Comparing the Survival Analysis of Two or More Groups
Bioequivalence Experimental Study Designs: Completely Randomized and Randomized Block Designs
Multiple Comparison Tests
It would be easy to compare two samples using a significance alpha level of 0.05. In other words, there is only one sample pair to be compared. However, it would be difficult to identify a significantly different sample if the number...
