Allocation Concealment in Clinical Trials—Reply

Abstract
In Reply: Dr Schulz and colleagues suggest that our results may differ from previous reports because definitions of quality measures, specifically allocation concealment, were not identical. Their point highlights a difficulty in applying quality measures and achieving consensus on precise definitions. We took great care to create definitions that were consistent with most prior applications of these quality measures and that were also unlikely to be misinterpreted by data extractors.1 We ended with very high agreement among data extractors.