Checks of Case Record Forms versus the Database for Efficacy Variables when Validation Programs Exist

Abstract

It is common practice in the pharmaceutical industry to perform checks of the computer database for a clinical study against the data on the case record forms. This check generally encompasses primary efficacy variables which are also the subject of programmed validation (edit) checks. The value of such checks for efficacy variables when validation programs exist is investigated under certain assumptions and conditions including a range of different data error rates and sample sizes. Simulations are used for smaller samples and an exact formula is derived from characteristic function theory for larger samples. Even in the face of high data error rates, the value of database checks is not justified for moderate or larger sample sizes. For data error rates typically observed in the industry, the loss of study power is minimal.