Objective: To systematically review the extent to which time to publication is influenced by the result of a clinical trial.

Methods: This presentation is the first step in a systematic review of studies assessing the extent to which time to publication is influenced by the result of a clinical trial. It will investigate the effect of both statistical significance and clinical significance. A preliminary search has been carried out to identify relevant studies in MEDLINE and the Cochrane Methodology Register. A more comprehensive search strategy is being developed. Studies will also be sought during the hand searching of Controlled Clinical Trials and Statistics in Medicine, which is being carried out by the UK Cochrane Centre for all studies relevant to the methodology of systematic reviews.

Results: There are at least seven published assessments of the influence a trial's results might have on the length of time taken for it to be published. In general, these show that trials with statistically significant results are more likely to be published sooner than those with non-significant results. However, at least one example has been found which does not appear to support this finding (although it is not clear if this should be considered as "no evidence of an effect" or "evidence of no effect"). Details of the identified studies, along with any others that are found in the interim, will be presented.
Conclusions: Our preliminary review confirms that trials with statistically significant results might be published sooner than those with non-significant results. This has important implications for the timing of the updating of reviews, especially if there is an association between the inclusion of a trial in a review and its publication status. It is of particular concern when one considers reviews in which only a small number of studies have been published and are available for the review.