Evidence-based medicine (EBM) is the use of the best evidence in combination with clinical expertise and patient values to guide medical decision-making for the individual patient. EBM is increasingly an important part of providing high value care and campaigns such as Choosing Wisely, an initiative that seeks to reduce unnecessary medical testing, treatment and procedures.

Five basic steps in practicing EBM:

1. ASK: Determine the clinical knowledge gap and construct a question.
2. ACQUIRE: Select the appropriate resources and search the literature for relevant data.
3. APPRAISE: Evaluate the evidence for validity (closeness to the truth) and applicability (usefulness to the patient).
4. APPLY: Integrate evidence with clinical expertise and patient preferences to make a clinical decision.
5. ASSESS: Reflect on the process and outcome for your patient to inform future practice.

Guidelines: Issued by government agencies and medical societies. They are generally derived from a combination of systematic reviews, meta-analyses, and expert consensus panel. Society-issued guidelines tend to be more aggressive (more mammograms, more CABGs) and government-issued guidelines are often more cost-conscious. At a minimum, guidelines should be judged by two criteria:

• The strength of the evidence: There is no consensus on how to categorize strength of evidence, but it can be generally derived from the quality of evidence and number of subjects (e.g. multiple RCTs vs limited non-randomized studies vs expert opinion).

The strength of the recommendation: Groups such as the United States Preventive Services Taskforce (USPSTF) or American College of Cardiology/ American Heart Association (ACC/AHA) offer tiers of recommendations (e.g. Class A, B or C) based on weighing the size and certainty of benefit of the intervention against the associated risks.