Two-thirds of methodological research remained unpublished after presentation at Cochrane Colloquia: an empirical analysis

Objectives: To determine the extent to which abstracts of methodology research, initially presented at annual meetings of The Cochrane Collaboration, have been published as full reports and over what period of time. A secondary aim was to explore whether full publication varied in different methodological subject areas. Study Design and Setting: The Cochrane Methodology Register (CMR) was searched for all abstracts reporting methodology research, presented at the 11 Cochrane Colloquia from 1997 to 2007. EMBASE, PubMed, and CMR were searched for full publications of the same research. Results: We identified 908 eligible conference abstracts and found full publications for 312 (34.4%) of these, almost half of which (47.1%) had appeared by the end of the first year after the relevant Colloquium. The proportion of abstracts that had not been published by 3 years was 69.7%, falling to 66.2% at 5 years. Publication varied considerably between different methodological areas. Conclusion: Approximately two-thirds of methodological research studies presented at Cochrane Colloquia remain unpublished as full papers at least 5 years later. This highlights the importance of searching conference abstracts if one wishes to find as comprehensive and complete a sample of methodological research as possible. (c) 2012 Elsevier Inc. All rights reserved.