Critical appraisal process: step-by-step.

We present information describing how to search to identify those reports that provide insight into the answer to the query. We have presented a reasonable approach to searching, with our end-point being the identification of published articles which appear to answer our queries. The decision as to whether these articles are applicable to the patient under discussion is determined by our clinical knowledge and the specifics of the patient's medical concerns. This process is recognized as critical analysis. Our structure for optimal searching includes use of the PICO model, formulating a focused clinical question, and defining key search terms. Using these principles, we have addressed an example important controversy in the practice of clinical medicine; in other words, the effectiveness of screening for prostate cancer and whether it alters the natural history of this illness.