The Composite Quality Score (CQS) as an Appraisal Tool for Prospective, Controlled Clinical Therapy Trials: Rationale and Current Evidence

Background: Current evidence appraisal concepts, such as the Assessment, Development and Evaluation (GRADE) approach and Cochrane’s Risk of Bias (RoB) tool, rely on assumptions related to the classic problem of inductive reasoning and may suffer from insufficient inter-rater reliability. Discussion: The Composite Quality Score (CQS) has emerged as a possible trial appraisal tool that does not rely on inductive assumptions and has been shown to be of potentially very high inter-rater reliability. Conclusion: Although the current CQS concept is still under development, its current evidence is encouraging and justifies further study. This article presents the rationale and currently available research concerning the CQS and shows where further research is required.