Systematic reviewers are advised to search trials registers to minimise risk of reporting biases. However, there has been little research on the impact of searching trials registers on the results of meta-analyses. We aimed to evaluate the impact of searching clinical trials registers for systematic reviews of pharmaceutical or non-pharmaceutical…

Background: Involving adults with cognitive impairments, and specifically intellectual disability, in research is critical to developing appropriate and effective interventions but is highly challenging. Our aim was to examine where complexities lie in delivering research in underrepresented and hard to reach populations using an exemplar process…

The practice of prospectively registering the details of intervention studies in a public database or registry is gaining momentum across disciplines as a strategy for increasing the transparency, credibility, and accessibility of study findings. In this article, we consider five registries that may be relevant for registration of intervention…

Many randomized trials evaluate an intervention effect on time-to-event outcomes. Individual participant data (IPD) from such trials can be obtained and combined in a so-called IPD meta-analysis (IPD-MA), to summarize the overall intervention effect. We performed a narrative literature review to provide an overview of methods for conducting an…

Clinical trial data are essential for assessments of the effectiveness of health care interventions. Information about ongoing or completed, but not yet formally published, trials has been more difficult to identify until the development of clinical trials registers and portals. This paper summarises research evidence on identifying sources of…