A significant proportion of clinical trials are not published in a timely fashion
A study in PLoS One earlier this year found that a relatively high proportion of completed US-based clinical trials did not achieve timely transparency either through publication in peer-review journals or by posting basic results to a website such as http://www.ClinicalTrials.gov. Roughly 30% of clinical studies failed to enter the public domain during the four years of follow-up. Even lower rates were seen for early phase, industry-funded trials. Factors predicting public disclosure of results of completed studies can be seen by clicking in the image below. The full publication of this study can be downloaded from the following link: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0101826.