Critical appraisal of research evidence for its validity and usefulness.

Step 3 in the evidence-based practice approach involves critical appraisal of the validity and usefulness of evidence. This process can be broken down into three sequential subcomponents having to do with validity, generalizability, and recommendation strength. Critical appraisal focuses on determining whether individual study conclusions are valid. This process can be assisted by the use of critical of appraisal forms, a wide variety of which exist. Forms vary according to structure, content, scoring, and emphasis. Recommendations to patients or within clinical practice guidelines should consider the quality of the evidence, the balance between desirable and undesirable effects, resource use, clinical experience, and patient preferences. Recently, an international collaboration (GRADE working group) has focused on defining common methods to grade recommendations clearly and consistently and has moved toward a system that integrates these factors to make either strong, weak, or no recommendation.