PRC Research Methods & Evidence-Based Practice 2 — Questions and Answers
Question 1: In a randomized controlled trial examining a PRI intervention, the 'allocation concealment' process is intended to prevent which of the following?
- Selection bias during participant assignment (Correct answer)
- Attrition bias at follow-up
- Detection bias during outcome measurement
- Reporting bias in publication
Correct answer: Selection bias during participant assignment
Allocation concealment prevents researchers from knowing upcoming assignments, eliminating the ability to selectively enroll participants into favorable groups.
Question 2: A PRC clinician wants to determine the minimal detectable change (MDC) for a breathing pattern assessment tool. Which statistic is most directly used to calculate MDC?
- Cronbach's alpha
- Standard error of measurement (SEM) (Correct answer)
- Intraclass correlation coefficient (ICC) alone
- Cohen's kappa
Correct answer: Standard error of measurement (SEM)
MDC is calculated using the SEM (MDC = SEM × 1.96 × √2), making SEM the foundational statistic for this determination.
Question 3: A systematic review of PRI outcomes uses the GRADE framework. Which factor would most likely DOWNGRADE the quality of evidence from 'high' to 'moderate'?
- A large pooled sample size across studies
- Significant unexplained heterogeneity (I² > 75%) (Correct answer)
- Consistent effect direction across all included studies
- Use of objective outcome measures
Correct answer: Significant unexplained heterogeneity (I² > 75%)
High statistical heterogeneity (I² > 75%) indicates substantial variability in study results that cannot be explained, which GRADE uses as grounds to downgrade evidence quality.
Question 4: When a PRI study reports a number needed to treat (NNT) of 4 for resolving asymmetrical respiratory patterns, this means:
- 4% of patients benefit from the intervention
- 4 patients must be treated for 1 additional patient to benefit beyond control (Correct answer)
- The intervention is 4 times more effective than placebo
- The relative risk reduction is 4:1
Correct answer: 4 patients must be treated for 1 additional patient to benefit beyond control
NNT represents how many patients must receive treatment for one additional patient to achieve the target outcome compared to the control condition.
Question 5: A researcher uses purposive sampling to select PRI-certified clinicians for a qualitative study on clinical decision-making. This sampling strategy is best described as:
- Random probability sampling to ensure representativeness
- Deliberate selection of participants based on specific characteristics relevant to the study (Correct answer)
- Convenience sampling of the nearest available participants
- Snowball sampling where participants recruit peers
Correct answer: Deliberate selection of participants based on specific characteristics relevant to the study
Purposive sampling involves intentional selection of participants who possess characteristics most informative to the research question, common in qualitative designs.
Question 6: In evidence-based PRI practice, the concept of 'clinical expertise' in the EBP triad primarily refers to:
- The number of years a clinician has been practicing
- The clinician's accumulated knowledge, judgment, and skills for individual patient assessment and management (Correct answer)
- Mastery of statistical analysis relevant to clinical outcomes
- Certification status and continuing education credits
Correct answer: The clinician's accumulated knowledge, judgment, and skills for individual patient assessment and management
Clinical expertise in the EBP framework encompasses the clinician's proficiency and judgment developed through experience in evaluating and treating individual patients.
Question 7: A cross-sectional study assesses the prevalence of left AIC pattern in 200 collegiate athletes. Which limitation is inherent to this study design?
- Inability to establish temporal sequence between exposure and outcome (Correct answer)
- High cost and long duration compared to longitudinal designs
- Requirement for a control group limits generalizability
- Blinding is impossible in cross-sectional designs
Correct answer: Inability to establish temporal sequence between exposure and outcome
Cross-sectional studies capture a snapshot in time, making it impossible to determine whether the postural pattern preceded or resulted from athletic participation.
PRC Research Methods & Evidence-Based Practice 2
In a randomized controlled trial examining a PRI intervention, the 'allocation concealment' process is intended to prevent which of the following?