DPT Research & Evidence-Based Practice 5 — Questions and Answers
Question 1: When critically appraising a diagnostic accuracy study, which tool is most commonly recommended?
- PEDro scale
- QUADAS-2 (Correct answer)
- Cochrane Risk of Bias Tool
- CONSORT checklist
Correct answer: QUADAS-2
QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies) is the standard appraisal tool specifically designed for diagnostic test accuracy studies.
Question 2: A physical therapist applies Bayesian reasoning to clinical decision-making. Which factor is updated using the likelihood ratio?
- Post-test probability (Correct answer)
- Sensitivity of the test
- Alpha level
- Effect size
Correct answer: Post-test probability
Likelihood ratios are applied to pre-test probability (prior probability) to calculate post-test probability of disease.
Question 3: A researcher conducting a cohort study controls for age, sex, and comorbidities using statistical analysis. This process is called:
- Blinding
- Randomization
- Multivariable adjustment (Correct answer)
- Stratified sampling
Correct answer: Multivariable adjustment
Multivariable (or multivariate) adjustment statistically controls for confounders when randomization is not possible, as in observational studies.
Question 4: Which level of the evidence hierarchy ranks BELOW randomized controlled trials but ABOVE case series?
- Systematic reviews with meta-analysis
- Expert opinion
- Cohort studies (Correct answer)
- Animal research
Correct answer: Cohort studies
Cohort and other well-designed observational studies rank below RCTs but above case series and expert opinion in the evidence hierarchy.
Question 5: A physical therapist wants to measure whether a lumbar stabilization program reduces disability using a validated PRO instrument. Which outcome measure is most appropriate?
- Visual Analog Scale for pain
- Oswestry Disability Index (ODI) (Correct answer)
- Berg Balance Scale
- Functional Independence Measure (FIM)
Correct answer: Oswestry Disability Index (ODI)
The Oswestry Disability Index is a validated patient-reported outcome measure specifically designed to quantify disability due to low back pain.
Question 6: A 95% confidence interval for a mean difference between groups is reported as (2.1 to 8.7). Which interpretation is correct?
- There is a 95% chance the true mean difference falls within this range
- If the study were repeated 100 times, approximately 95 of the resulting CIs would contain the true parameter (Correct answer)
- The intervention definitely produces a clinically important benefit
- The p-value is exactly 0.05
Correct answer: If the study were repeated 100 times, approximately 95 of the resulting CIs would contain the true parameter
A 95% CI means that if the study were replicated many times, 95% of the resulting confidence intervals would capture the true population parameter.
Question 7: A PT wants to implement a clinical guideline but finds that the recommendation is based on expert consensus with no supporting RCTs. According to GRADE, this evidence would be rated as:
- High quality
- Moderate quality
- Low quality
- Very low quality (Correct answer)
Correct answer: Very low quality
Expert consensus opinion without empirical research support is classified as Very Low quality evidence under the GRADE framework.
DPT Research & Evidence-Based Practice 5
When critically appraising a diagnostic accuracy study, which tool is most commonly recommended?