Non-randomized studies in Cochrane reviews of intervention studies: A content analysis

Although a growing number of Cochrane reviews of intervention studies have included non-randomized studies, how and why these studies have been included has not been evaluated to date. In this plenary, Jani Ruotsalainen, managing editor of the Cochrane Occupational Safety and Health Review Group, talks about the practice of including non-randomized studies in Cochrane systematic reviews, focusing on the reasons why these studies were included. He also looks at the methods used by the studies to assess risk of bias.