Introduction: The assessment of the quality of reporting of randomised controlled trials included in meta-analysis remains controversial. Some researchers see quality assessment as a source of bias or as completely uninformative, while others regard it as an important strategy to identify and reduce bias. The amount of empirical evidence to inform these extreme positions, however, is insufficient. This study is part of a larger project that attempts to generate the empirical evidence necessary to resolve the controversy.

Objective: To estimate the proportion of published meta-analysis in which the quality of randomised controlled trials has been assessed, and the methods used to obtain and incorporate the assessments into the results of the meta-analyses.

Methods: We selected two populations of meta-analyses of randomised controlled trials: 36 from the Cochrane Database of Systematic Reviews, and 204 selected randomly from Medline. Each meta-analysis is being evaluated using 28 different questions related to quality assessment. The reviewers are completing the evaluations in pairs, masked to all journal identifiers. Before completing these assessments an inter-observer reliability study was completed using 10 separate meta-analyses.

Results: We will present descriptive and comparative results on the individual items assessed. We will also present time trends of quality assessment.