has part has_specified_input has_specified_output count false positive rate between group comparison statistical test interim analysis Pocock boundary analysis Philippe Rocca-Serra The Pocock boundary analysis gives a p-value threshold for each interim analysis which guides the data monitoring committee on whether to stop the trial. The boundary used depends on the number of interim analyses. The Pocock boundary is simple to use in that the p-value threshold is the same at each interim analysis. The disadvantages are that the number of interim analyses must be fixed at the start and it is not possible under this scheme to add analyses after the trial has started. Another disadvantage is that investigators and readers frequently do not understand how the p-values are reported: for example, if there are five interim analyses planned, but the trial is stopped after the third interim analysis because the p-value was 0.01, then the overall p-value for the trial is still reported as <0.05 and not as 0.01. As all frequentist methods of the same type, it focuses on controlling the type I error rate as the repeated hypothesis testing of accumulating data increases the type I error rate of a clinical trial. https://doi.org/10.1093%2Fbiomet%2F64.2.191 and Wikipedia: https://en.wikipedia.org/wiki/Pocock_boundary https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3856440/ p-value ready for release