Background: Reporting of health research is often inadequate. To this end, many reporting guidelines (RGs), aimed at improving the quality of health research reports, have been developed for reporting a wide variety of specific types of research. A RG typically consists of a checklist, flow diagram or explicit text to guide authors on what should be included in a research report. Despite their emergence, RGs are underused and published health research continues to be poorly reported. Synthesizing evidence of their impact on the quality of reporting will help identify the most effective guidelines and motivate their use.

Objective: To systematically review and, where possible, synthesize evidence on the impact of RGs on the overall transparency of health research reporting.

Methods: This systematic review will investigate the impact of 81 RGs identified by an earlier systematic review, as well as newly eligible guidelines identified by the EQUATOR Network. A search strategy has been designed to identify evaluations of each RG. We will explore characteristics of RGs and journals associated with their use. Analysis methods will follow those of a recently completed systematic review of evaluations of the CONSORT Statement - a reporting guideline for randomized trials. Preliminary findings for this review will be presented at the Cochrane Colloquium. potential Impact: This project aims to provide evidence to help guide decision making for journal editors. Knowledge translation activities will include a meeting of journal editors to help develop next steps for RG implementation based on the results of this review, since it is likely a prudent policy to endorse and adhere to those RGs for which there is some evidence on their effectiveness. Ultimately, this review will help increase the uptake of RGs by different user groups and contribute to the improvement in health research reporting.