Introduction
Evidence-based medicine (EBM) is essential for M.Pharm students aiming to optimize medication use through scientifically supported decisions. This blog presents focused multiple-choice questions that cover core EBM concepts and practical skills: forming answerable clinical questions, searching and appraising literature, interpreting measures of effect, understanding trial methodology, and applying evidence to individual patients. Questions emphasize critical appraisal, statistical interpretation (confidence intervals, p-values, heterogeneity), meta-analysis principles, bias recognition, guideline development and shared decision-making. Each MCQ includes plausible distractors and clear answers to reinforce learning, promote deeper thinking about study design and interpretation, and prepare you for exams and clinical practice where rational, patient-centered pharmacotherapy matters.
Q1. What is the best concise definition of evidence-based medicine (EBM)?
- Using only randomized trials to guide all clinical decisions
- Integrating individual clinical expertise with the best available external clinical evidence and patient values
- Relying on expert opinion and textbooks as primary decision sources
- Applying local formulary restrictions to standardize therapy
Correct Answer: Integrating individual clinical expertise with the best available external clinical evidence and patient values
Q2. Which sequence correctly lists the classical five steps of practicing EBM?
- Apply, Ask, Appraise, Acquire, Assess
- Ask, Acquire, Appraise, Apply, Assess
- Ask, Appraise, Acquire, Apply, Audit
- Acquire, Ask, Appraise, Apply, Act
Correct Answer: Ask, Acquire, Appraise, Apply, Assess
Q3. In the PICO framework used to frame clinical questions, what does the letter “C” usually represent?
- Cost of intervention
- Clinical outcome
- Comparison or comparator
- Case series
Correct Answer: Comparison or comparator
Q4. Which type of study is generally considered the highest level of evidence for judging intervention effectiveness?
- Case-control study
- Randomized controlled trial
- Systematic review with meta-analysis of randomized trials
- Expert consensus guideline
Correct Answer: Systematic review with meta-analysis of randomized trials
Q5. What is the primary methodological feature that distinguishes a randomized controlled trial (RCT) from non-randomized studies?
- Use of a control group
- Random allocation of participants to intervention groups
- Blinding of outcome assessors
- Prospective follow-up of participants
Correct Answer: Random allocation of participants to intervention groups
Q6. Allocation concealment in randomized trials is most important to prevent which problem?
- Performance bias after randomization
- Selection bias before or at the point of randomization
- Detection bias during outcome assessment
- Attrition bias due to loss to follow‑up
Correct Answer: Selection bias before or at the point of randomization
Q7. Blinding participants and personnel in a trial primarily reduces which type(s) of bias?
- Selection bias only
- Performance and detection bias
- Publication bias
- Confounding by indication
Correct Answer: Performance and detection bias
Q8. Why is an intention-to-treat (ITT) analysis recommended in randomized trials?
- It excludes participants who did not adhere to the protocol to show the maximal drug effect
- It preserves the benefits of randomization and reduces bias from post-randomization exclusions
- It increases statistical power by removing dropouts
- It allows investigators to change outcomes after seeing the data
Correct Answer: It preserves the benefits of randomization and reduces bias from post-randomization exclusions
Q9. A reported relative risk (RR) for an adverse event with treatment versus control is 0.5. How should this be interpreted?
- The risk is increased by 50% with treatment
- The risk is reduced by 50% with treatment
- The absolute risk reduction is 50% with treatment
- The number needed to treat is 0.5
Correct Answer: The risk is reduced by 50% with treatment
Q10. If the event rate is 20% in the control group and 10% in the treatment group, what is the number needed to treat (NNT) to prevent one event?
- 5
- 10
- 20
- 50
Correct Answer: 10
Q11. Under which condition is an odds ratio (OR) a reasonable approximation of the relative risk (RR)?
- When outcome is common (>20%)
- When outcome is rare (<10%)
- When sample size is very small
- When using adjusted analyses only
Correct Answer: When outcome is rare (<10%)
Q12. A 95% confidence interval for a relative risk is 0.85 to 1.12. What does this imply about statistical significance at the 0.05 level?
- The result is statistically significant because the interval is narrow
- The result is not statistically significant because the interval includes 1
- The p-value must be less than 0.01
- The point estimate is invalid
Correct Answer: The result is not statistically significant because the interval includes 1
Q13. In meta-analysis, what does an I² value of 65% most likely indicate?
- Low heterogeneity between studies
- Moderate to substantial heterogeneity between studies
- No heterogeneity; all variation is due to chance
- High publication bias
Correct Answer: Moderate to substantial heterogeneity between studies
Q14. Which statement best distinguishes fixed-effect and random-effects meta-analysis models?
- Fixed-effect assumes a single true effect size common to all studies; random-effects allows study-level variation in true effects
- Fixed-effect adjusts for publication bias; random-effects does not
- Fixed-effect is used only for binary outcomes; random-effects only for continuous outcomes
- Fixed-effect produces wider confidence intervals than random-effects in all cases
Correct Answer: Fixed-effect assumes a single true effect size common to all studies; random-effects allows study-level variation in true effects
Q15. Asymmetry in a funnel plot is most commonly interpreted as evidence of which issue?
- High internal validity of included studies
- Publication bias or small-study effects
- Correct randomization across trials
- Perfect homogeneity of treatment effects
Correct Answer: Publication bias or small-study effects
Q16. Which of the following is NOT one of the primary domains used by the GRADE system to downgrade the quality of evidence?
- Risk of bias
- Inconsistency
- Indirectness
- Sample size calculation plan
Correct Answer: Sample size calculation plan
Q17. What does the sensitivity of a diagnostic test measure?
- The proportion of true negatives correctly identified
- The proportion of true positives correctly identified
- The probability that a positive test result rules out disease
- The prevalence of disease in the tested population
Correct Answer: The proportion of true positives correctly identified
Q18. How is the positive likelihood ratio (LR+) for a diagnostic test calculated?
- Sensitivity divided by (1 − Specificity)
- Specificity divided by (1 − Sensitivity)
- Sensitivity − Specificity
- (1 − Sensitivity) / Specificity
Correct Answer: Sensitivity divided by (1 − Specificity)
Q19. Which statement about predictive values of diagnostic tests is correct?
- Positive predictive value (PPV) is independent of disease prevalence
- Negative predictive value (NPV) increases as disease prevalence increases
- Both PPV and NPV vary with disease prevalence in the tested population
- Predictive values depend only on test sensitivity, not specificity
Correct Answer: Both PPV and NPV vary with disease prevalence in the tested population
Q20. In evidence-based prescribing, what does shared decision-making primarily emphasize?
- Physician making the decision based on clinical guidelines alone
- Using the most expensive therapy to ensure efficacy
- Combining best evidence with the patient’s values, preferences and circumstances
- Avoiding patient involvement to prevent confusion
Correct Answer: Combining best evidence with the patient’s values, preferences and circumstances
