Deduplicating records in systematic reviews: there are free, accurate automated ways to do so

•Accurate automated tools could reduce subjectivity and help researchers spare time to search for appropriate answers to specific guiding questions and, ultimately, to underpin clinical and policy decisions.•Rayyan, Mendeley, and Systematic Review Accelerator proved to be accurate enough for the deduplication step of systematic reviews.•Our results on accuracy parameters from the available main automated tools could help researchers choose the most suitable tool based on a set of empirically defined values to conduct deduplication steps in systematic review studies.