Study screening and selection

Study screening and selection will be done manually within the EndNote based on the inclusion and exclusion criteria for this systematic review. To ensure the availability of study protocols, we will limit the search to CRTs that have the word stem “regist*” in the abstract and use these results to begin the process of screening and selection. We validated this procedure by examining a subset of excluded articles. Screening and selection will be done in two stages by two independent reviewers (MCP and NM). In the first stage, reviewers will independently screen the titles and abstracts of each identified reference against the inclusion criteria to eliminate irrelevant publications. In the second stage, we will screen the full text of all studies that appear to meet the inclusion criteria or for which there is uncertainty as to eligibility. For each study, we will identify additional articles of potential relevance, such as a published protocol or a process evaluation, by reviewing references from the main trial report, consulting the trial registry record, and searching the PubMed database for new publications by the lead trial author. To aid in article screening and selection, the team will develop and test a screening sheet for full-text review. Any disagreement between reviewers will be resolved through discussion and, as necessary, through arbitration by a third author (MJ). The process of study selection will be documented in a flow diagram describing studies identified and excluded at each stage. We will also provide a summary table describing studies excluded at the stage of full-text review, along with reasons for their exclusion.