Ethics, Professionalism, Research, and Evidence-Based Practice
Ethics questions test the four principles - autonomy, beneficence, non-maleficence and justice - applied to consent, capacity, confidentiality and resource allocation. A competent pregnant woman can refuse any intervention, including caesarean delivery, even when the fetus is at risk; assess capacity formally when refusal seems unreasonable. The duty of candour requires disclosure of harmful errors. Research ethics requires ethical approval, informed consent, and special protection for pregnant women, children and prisoners.
Evidence-based practice requires understanding study design: randomised controlled trials for therapy, cohort and case-control studies for prognosis and rare exposures, systematic reviews for synthesis. The hierarchy runs from systematic reviews of randomised trials down to expert opinion, and observational studies can show association but not causation. Sensitivity and specificity describe the test; positive and negative predictive values depend on prevalence, so a good test in a low-prevalence population yields many false positives. The number needed to treat is the reciprocal of the absolute risk reduction.
Traps: quoting a p-value as a measure of effect size; confusing screening with diagnosis; equating audit with research; and forgetting that relative risk reductions sound larger than absolute ones.
Rule of thumb: sensitivity is a property of the test, but predictive value depends on how common the disease is in the population tested.