In a best case scenario, you will be able to find a high quality pre-appraised information source to answer your question.
However, those are not available for all topics. Furthermore, you may also find it useful to appraise pre-appraised information. You should always question the quality of the material you find. Remember, a poorly done systematic review is not better than a well done randomized controlled trial. On this page, you will find some resources to help you with appraising the material you find.
This resource includes both the User's Guides to the Medical Literature and the Rational Clinical Exam. There are great explanations for critically appraising different study types along with worksheets and PowerPoints that can be reused for educational purposes.
High-Yield(tm) Biostatistics, Epidemiology, and Public Health, Fourth Edition provides a concise review of the biostatistics concepts that are tested in the USMLE Step 1. Information is presented in an easy-to-follow format, with High-Yield Points that help students focus on the most important USMLE Step 1 facts. The High-Yield(tm) outline format, with tables, diagrams, photographs, and images to clarify important material, provides a concentrated, efficient review for both course exams and the USMLE.