Abstract

To explore opinions of authors of published reports of clinical trials and Cochrane systematic reviews on the causes and methods of preventing publication bias.An online questionnaire was developed and sent to researchers publishing in high-impact or national general medical journals, authors of Cochrane systematic reviews, and a general population of researchers. Open-ended questions about publication bias were qualitatively analyzed. We also held a focus group with experienced researchers and/or Cochrane reviewers.Publication bias was common: 48 (36%) respondents had own unpublished trials and 40 (30%) admitted selective outcome reporting; but researchers felt strongly that blame rested also with the system that promotes and augments publication bias practices. Qualitative analysis of both survey responses and focus group discussion identified possible ways of reducing publication bias through increased transparency, improvements to trial registries, search engines and databases, enhancement of the role of institutional review boards, positive encouragement of scientists, and policy changes.Although well aware of the problem, clinical researchers knowingly contribute to problems of selective reporting and nonpublication of trials. They call for changes in current practices of journal-based communication of trial reporting and for systematic evaluation of measures to decrease publication bias.