DPT Research & Evidence-Based Practice 4 — Questions and Answers
Question 1: A PT searches PubMed using the PICO format. What does the 'C' in PICO represent?
- Clinical setting
- Comparison intervention (Correct answer)
- Cost-effectiveness
- Co-morbid condition
Correct answer: Comparison intervention
In the PICO framework, C stands for Comparison, which identifies the alternative intervention or control condition against which the intervention is compared.
Question 2: Which statistic is most appropriate to report when describing the central tendency of a skewed dataset (e.g., length of hospital stay)?
- Mean
- Standard deviation
- Median (Correct answer)
- Variance
Correct answer: Median
The median is preferred over the mean for skewed distributions because extreme outliers do not distort it.
Question 3: An investigator finds a correlation of r = 0.85 between hip abductor strength and balance scores. Which conclusion is most appropriate?
- Hip strength causes better balance
- There is a strong positive association between the two variables (Correct answer)
- 85% of patients with hip weakness will fall
- The relationship is clinically significant at α = 0.05
Correct answer: There is a strong positive association between the two variables
Correlation describes the strength and direction of association; it does not establish causation between variables.
Question 4: Which study design is most efficient for investigating rare adverse events following a physical therapy intervention?
- Randomized controlled trial
- Cohort study
- Case-control study (Correct answer)
- Cross-sectional study
Correct answer: Case-control study
Case-control studies work backward from outcome to exposure, making them efficient for rare outcomes because cases are selected directly.
Question 5: A researcher uses an ITT (intention-to-treat) analysis. What is the primary advantage of this approach?
- It excludes non-compliant participants to improve effect estimates
- It preserves the benefits of randomization and reflects real-world effectiveness (Correct answer)
- It increases statistical power by removing outliers
- It focuses on participants who received the full intervention protocol
Correct answer: It preserves the benefits of randomization and reflects real-world effectiveness
ITT analysis includes all randomized participants regardless of adherence, preserving allocation balance and providing an unbiased effectiveness estimate.
Question 6: A PT reads a meta-analysis that reports an I² value of 78%. What does this indicate about the included studies?
- The studies have low statistical heterogeneity
- There is substantial heterogeneity among the included studies (Correct answer)
- 78% of the variance is explained by the intervention
- The pooled estimate is highly reliable
Correct answer: There is substantial heterogeneity among the included studies
An I² of 75% or higher indicates substantial heterogeneity, suggesting the studies may not be measuring the same underlying effect.
Question 7: Which term describes the smallest change in an outcome measure that is meaningful from the patient's perspective?
- Standard error of measurement (SEM)
- Minimal detectable change (MDC)
- Minimal clinically important difference (MCID) (Correct answer)
- Coefficient of variation (CV)
Correct answer: Minimal clinically important difference (MCID)
The MCID is the smallest change in a patient-reported outcome that the patient perceives as beneficial and would warrant a change in management.
DPT Research & Evidence-Based Practice 4
A PT searches PubMed using the PICO format.
What does the 'C' in PICO represent?