Among a sample of meta-analyses from the database, individual components and scales were the methods most commonly used to assess trial quality. However when quality assessments were made, in most cases they were not incorporated into the analysis. This is important because the incorporation of quality assessments can alter the estimate of the benefit of intervention, regardless of which method of assessment is used. The results from these studies also suggest that certain characteristics of the design and execution of RCTs impact on the probability of bias, and further research is needed on this. Investigations are also needed to clarify the value of masking studies before quality assessment and to determine the advantages of the various approaches to incorporate quality assessments into the analyses.
Guidelines is a bullet.
The quality of all randomised trials included in a meta-analysis should be assessed. Masked quality assessment should be considered, and meta-analysts should report masking methods used or their reasons for rejecting masking. Scales used for assessment should have been appropriately developed and evaluated. A component approach has the advantage that it can be topic-specific. However, there is no compelling evidence to recommend a component approach over a scale approach or vice versa.