A test method for identifying selection bias risk in prospective controlled clinical therapy trials using the I2 point estimate (Preprint)

Abstract Objectives: A test method is proposed for identifying potential selection bias risk in single prospective controlled clinical therapy trials that can be applied by trial reviewers. Methods: The method is described in detail and was tested on eight randomised controlled trials (RCT) with reported negative Berger-Exner test result as negative and on eight prospective, controlled COHORT studies as positive controls. All 16 studies were identified by systematic literature search. Results: The test method yielded negative results for all RCTs and positive results for 6 out of the 8 COHORT studies. Conclusion: All test results remained within the expected limits for both study types, suggesting a reasonably high accuracy for correctly identifying selection bias risk. However, the method does not provide the possibility to establish whether such bias risk has actually altered trial outcome. Instead, a positive test result may provide an empirical basis for rating a trial as of high selection bias risk during trial appraisal.