MPT Research Methods and Evidence-Based Practice 1 — Questions and Answers
Question 1: According to the hierarchy of evidence, which study design provides the strongest evidence for clinical decision-making?
- Expert opinion and clinical guidelines
- Case reports and case series
- Systematic review with meta-analysis (Correct answer)
- Randomized controlled trial
Correct answer: Systematic review with meta-analysis
Systematic reviews with meta-analysis sit at the top of the evidence hierarchy because they synthesize findings from multiple high-quality studies to produce pooled estimates.
Question 2: A study reports a p-value of 0.03. What does this most accurately indicate?
- There is a 3% chance the intervention is clinically effective
- There is a 3% probability of obtaining results as extreme as observed if the null hypothesis is true (Correct answer)
- The effect size is small but meaningful
- The sample size was adequate for the study
Correct answer: There is a 3% probability of obtaining results as extreme as observed if the null hypothesis is true
A p-value represents the probability of observing results as extreme as those obtained assuming the null hypothesis is true, not the probability that the treatment works.
Question 3: Which research design is most appropriate for establishing cause-and-effect relationships between an intervention and an outcome?
- Cross-sectional study
- Case-control study
- Cohort study
- Randomized controlled trial (Correct answer)
Correct answer: Randomized controlled trial
Randomized controlled trials are the gold standard for establishing causality because randomization distributes confounders equally and allows direct comparison of treatment effects.
Question 4: Internal validity in a research study refers to:
- The degree to which results can be generalized to other populations
- The accuracy of the measurement instruments used
- The extent to which the study design supports valid conclusions about cause and effect within the study (Correct answer)
- The consistency of measurements across different raters
Correct answer: The extent to which the study design supports valid conclusions about cause and effect within the study
Internal validity reflects how well the study controls for confounders and biases, allowing valid causal conclusions to be drawn about the relationship studied.
Question 5: A researcher rejects the null hypothesis when it is actually true. This error is classified as:
- Type II error
- Beta error
- Type I error (Correct answer)
- Power error
Correct answer: Type I error
A Type I error (alpha error) is a false positive — incorrectly rejecting a true null hypothesis, with the probability set by the alpha level (commonly 0.05).
Question 6: What is the primary purpose of randomization in a randomized controlled trial?
- To increase the overall sample size of the study
- To distribute known and unknown confounding variables equally between groups (Correct answer)
- To ensure that participants and researchers are blinded
- To improve the external validity and generalizability of findings
Correct answer: To distribute known and unknown confounding variables equally between groups
Randomization ensures that both known and unknown confounding variables are distributed equally across groups, thereby minimizing selection bias.
Question 7: A systematic review differs from a narrative review primarily because it:
- Includes a greater number of articles
- Uses explicit, predefined, and reproducible methods to search, select, and appraise evidence (Correct answer)
- Is always conducted by multiple authors or research teams
- Focuses exclusively on a single clinical condition or diagnosis
Correct answer: Uses explicit, predefined, and reproducible methods to search, select, and appraise evidence
Systematic reviews follow transparent, reproducible protocols for literature searching, study selection, and quality appraisal, minimizing bias compared to narrative reviews.
MPT Research Methods and Evidence-Based Practice 1
According to the hierarchy of evidence, which study design provides the strongest evidence for clinical decision-making?