Independence of the statistician who analyses unblinded data.

This discussion considers arguments for and against separating responsibility for the unblinded interim analysis of a clinical trial from responsibility for trial management and modifications to the ongoing trial. The degree to which one or different statisticians carry out these responsibilities and thus the degree of statistician independence for the two activities can vary, but a sponsor should recognize that giving a single statistician both responsibilities might limit flexibility in managing the trial, particularly with respect to modifying an ongoing trial.