A new study published in the online journal Public Library of Science (PLoS) Medicine on 24 May scrutinizes the quality of systematic reviews indexed in MEDLINE. The study found that the quantity of systematic reviews has increased significantly during the decade between 2004 and 2014 – tripling in number during that period – but that the quality, particularly of conduct and reporting, continues to be variable.
The study, entitled ‘Epidemiology and reporting characteristics of systematic reviews of biomedical research: a cross-sectional study’, was completed by an international team of researchers, led by Cochrane contributors David Moher and Matthew Page. They assessed a cross-section of all systematic reviews indexed in Medline in February 2014, identifying 682 and carrying out further analysis on a random sample of 300. They found that at least one-third of these reviews neither reported on how their authors had searched for studies, assessed the quality of studies included, nor used statistical methods generally approved as valid by the systematic reviewing community.
Among other findings relevant to Cochrane, the authors described completeness of reporting in Cochrane Reviews as ‘more complete…than in all other types of [systematic reviews]’. Their recommendations, based upon the study’s findings, focus on developing strategies to improve and standardize the conduct of systematic reviews, and thereby reduce research waste.