Q.1 What is the primary goal of Evidence-Based Medicine (EBM)?
To rely only on clinical intuition
To use the best available evidence in decision-making
To eliminate the need for clinical expertise
To depend solely on patient preferences
Explanation - EBM integrates clinical expertise, patient values, and the best research evidence to guide healthcare decisions.
Correct answer is: To use the best available evidence in decision-making
Q.2 Which of the following is the highest level of evidence in the evidence hierarchy?
Case reports
Randomized controlled trials (RCTs)
Systematic reviews and meta-analyses
Expert opinion
Explanation - Systematic reviews and meta-analyses combine results from multiple RCTs, making them the strongest form of evidence.
Correct answer is: Systematic reviews and meta-analyses
Q.3 What does PICO stand for in EBM?
Patient, Intervention, Comparison, Outcome
Problem, Information, Care, Observation
Population, Investigation, Case, Outcome
Patient, Indication, Control, Observation
Explanation - PICO is a framework for formulating clinical questions in evidence-based practice.
Correct answer is: Patient, Intervention, Comparison, Outcome
Q.4 In the hierarchy of evidence, where does expert opinion usually fall?
Highest level
Second highest level
Second lowest level
Lowest level
Explanation - Expert opinion is considered the weakest form of evidence since it lacks rigorous scientific validation.
Correct answer is: Lowest level
Q.5 Which type of study is best suited to determine causality?
Case-control study
Cohort study
Randomized controlled trial
Cross-sectional study
Explanation - RCTs are designed to test causality by randomizing participants and controlling confounding variables.
Correct answer is: Randomized controlled trial
Q.6 What does 'systematic review' mean?
A narrative summary of medical literature
A structured summary of multiple studies with critical appraisal
A single clinical trial report
An expert's personal interpretation
Explanation - Systematic reviews use a structured process to evaluate and summarize evidence from multiple studies.
Correct answer is: A structured summary of multiple studies with critical appraisal
Q.7 Which study design is most prone to recall bias?
Cohort study
Case-control study
Randomized controlled trial
Cross-sectional study
Explanation - Case-control studies rely on participants' recall of past exposures, making them prone to recall bias.
Correct answer is: Case-control study
Q.8 What is the primary purpose of meta-analysis?
To combine results from several studies to improve statistical power
To generate new hypotheses
To summarize expert opinion
To design new clinical guidelines
Explanation - Meta-analysis pools data from multiple studies to increase accuracy and detect true effects.
Correct answer is: To combine results from several studies to improve statistical power
Q.9 Which of the following best defines 'bias' in research?
Random variation in study outcomes
Systematic error that distorts study results
Increased statistical power
Unpredictable chance error
Explanation - Bias refers to systematic deviations from the truth due to study design, conduct, or analysis.
Correct answer is: Systematic error that distorts study results
Q.10 Which of the following best describes 'confounding'?
Error due to random chance
Distortion of association by another factor
A flaw in statistical software
An unavoidable limitation of RCTs
Explanation - Confounding occurs when a third factor affects both exposure and outcome, distorting the true relationship.
Correct answer is: Distortion of association by another factor
Q.11 Which statistical measure is commonly used in meta-analysis to express combined results?
Relative risk
Hazard ratio
Odds ratio
Pooled effect size
Explanation - Meta-analyses summarize data from multiple studies into a pooled effect size for interpretation.
Correct answer is: Pooled effect size
Q.12 What is the main limitation of cross-sectional studies?
They cannot establish temporal relationships
They are too expensive
They take too long to conduct
They require randomization
Explanation - Cross-sectional studies only provide a snapshot in time, making it difficult to assess cause-and-effect.
Correct answer is: They cannot establish temporal relationships
Q.13 Which type of bias occurs when published studies are more likely to have positive results?
Recall bias
Publication bias
Selection bias
Information bias
Explanation - Publication bias occurs when studies with negative or null results are less likely to be published.
Correct answer is: Publication bias
Q.14 What does 'intention-to-treat analysis' mean in RCTs?
Including only patients who completed the study
Analyzing patients according to their original group assignment
Excluding patients with missing data
Randomizing patients midway through the study
Explanation - Intention-to-treat analysis preserves randomization and avoids bias by analyzing all patients in their assigned groups.
Correct answer is: Analyzing patients according to their original group assignment
Q.15 Which measure is best for determining the strength of association in case-control studies?
Relative risk
Odds ratio
Hazard ratio
Absolute risk reduction
Explanation - Case-control studies use odds ratios because incidence rates cannot be directly calculated.
Correct answer is: Odds ratio
Q.16 Which type of error occurs when a study fails to detect an effect that actually exists?
Type I error
Type II error
Random error
Measurement error
Explanation - Type II error occurs when a study incorrectly accepts the null hypothesis despite a real effect.
Correct answer is: Type II error
Q.17 What is the primary advantage of randomized controlled trials?
They are inexpensive
They eliminate all forms of bias
They minimize confounding by random allocation
They provide immediate results
Explanation - Randomization helps distribute confounders evenly, strengthening causal inference.
Correct answer is: They minimize confounding by random allocation
Q.18 What is the 'null hypothesis' in clinical research?
That there is no difference or effect
That the new treatment is superior
That confounding exists
That bias cannot be avoided
Explanation - The null hypothesis assumes no association or effect between studied variables.
Correct answer is: That there is no difference or effect
Q.19 Which factor reduces external validity of a study?
Small sample size
Narrow inclusion criteria
Randomization
Use of control group
Explanation - Restrictive criteria limit generalizability, reducing external validity.
Correct answer is: Narrow inclusion criteria
Q.20 What does 'systematic error' refer to in EBM?
Error due to chance variation
Consistent bias affecting results
Random misclassification
Statistical noise
Explanation - Systematic error reflects bias in study design or execution that skews findings.
Correct answer is: Consistent bias affecting results
Q.21 Which study design is most useful for rare diseases?
Case-control study
Cohort study
RCT
Cross-sectional study
Explanation - Case-control studies are efficient for rare diseases since they start with cases and compare exposures.
Correct answer is: Case-control study
Q.22 What is the main disadvantage of cohort studies?
They cannot measure incidence
They are prone to recall bias
They require long follow-up and large samples
They cannot assess temporal sequence
Explanation - Cohort studies are resource-intensive but valuable for studying incidence and temporal sequence.
Correct answer is: They require long follow-up and large samples
Q.23 What is the primary measure of treatment effect in randomized controlled trials?
Relative risk
Odds ratio
P-value
Incidence density
Explanation - Relative risk compares outcomes in treatment and control groups, providing a direct measure of effect.
Correct answer is: Relative risk
Q.24 Which value indicates the probability of obtaining results by chance if the null hypothesis is true?
Confidence interval
P-value
Relative risk
Hazard ratio
Explanation - The P-value quantifies the probability of results arising by chance under the null hypothesis.
Correct answer is: P-value
Q.25 Which of the following improves precision of study results?
Larger sample size
Narrow confidence intervals
Random error
Short follow-up
Explanation - Increasing sample size reduces random error, improving precision.
Correct answer is: Larger sample size