Evidence-Based Medicine

Evidence-based medicine requires clinical decisions to integrate the best available research evidence with the clinician's expertise and the individual patient's values, preferences and circumstances. It is therefore neither mechanical adherence to guidelines nor reliance on professional opinion alone.

Core requirements in decision-making

The clinician should follow a transparent process that connects a patient's problem to reliable evidence and an appropriate course of action.

• Frame the clinical problem as an answerable question concerning matters such as diagnosis, treatment, prognosis or harm.
• Search systematically for the best available evidence, rather than selecting only information that supports a preferred conclusion.
• Critically appraise the evidence for methodological validity, effect size, relevance and applicability to the patient.
• Combine the evidence with clinical expertise and the patient's informed preferences, comorbidities, risks, costs and social circumstances.
• Monitor outcomes and revise the decision when the patient's response or the evidence changes.

How evidence should be interpreted

Evidence must be judged according to the question being asked. For treatment effectiveness, well-conducted randomised controlled trials and systematic reviews generally provide stronger causal evidence, while other study designs may be more appropriate for diagnosis, prognosis, rare harms or circumstances where trials are infeasible or unethical.

• The quality of a study matters, so a poorly conducted study does not become reliable merely because of its design label.
• Statistical significance alone is insufficient; clinical significance, benefits, harms and uncertainty must also be considered.
• Guidelines and standard treatment protocols support decisions, but they require application to the individual patient rather than automatic compliance.

Why the principle matters

Evidence-based practice promotes effective and safe care, limits ineffective or harmful interventions, and makes clinical reasoning more accountable. Shared decision-making also respects patient autonomy because choices are explained through their likely benefits, risks and alternatives.