A research team is conducting a review of the literature on the use of low-dose aspirin for preventing preeclampsia. Before beginning their search, they draft a protocol in which they define their clinical question, specify inclusion and exclusion criteria, and plan to search multiple databases, registries, and conference abstracts. They intend to appraise the quality of each study and summarize the findings without pooling numerical data. Which of the following characteristics most distinctly identifies this approach as a systematic review rather than another type of literature review?