CFO Research Methods & Evidence-Based Practice 3 — Questions and Answers
Question 1: In an orthotic outcomes study, a control group receiving a sham orthosis is used primarily to control for:
- Operator error during fitting
- Placebo effect and non-specific treatment effects (Correct answer)
- Measurement instrument reliability
- Interrater variability among clinicians
Correct answer: Placebo effect and non-specific treatment effects
A sham orthosis controls for placebo effects and patient expectations that may independently improve outcomes.
Question 2: Sensitivity of a clinical diagnostic test is defined as the ability to:
- Correctly identify individuals without the condition (true negatives)
- Correctly identify individuals with the condition (true positives) (Correct answer)
- Measure consistent results across repeated administrations
- Predict long-term functional outcomes in orthotics patients
Correct answer: Correctly identify individuals with the condition (true positives)
Sensitivity = true positives / (true positives + false negatives), reflecting how well the test detects those who have the condition.
Question 3: Which statistical measure describes the strength and direction of the linear relationship between two continuous variables in orthotic research?
- Odds ratio
- Pearson correlation coefficient (Correct answer)
- Chi-square statistic
- Number needed to treat
Correct answer: Pearson correlation coefficient
The Pearson correlation coefficient (r) quantifies the strength and direction of a linear relationship between two continuous variables.
Question 4: A prospective cohort study in orthotics follows participants:
- Backward in time from outcome to exposure
- Forward in time from exposure to outcome (Correct answer)
- In a randomized sequence with blinded allocation
- In alternating periods of treatment and washout
Correct answer: Forward in time from exposure to outcome
Prospective cohort studies enroll participants based on exposure status and follow them forward in time to observe outcomes.
Question 5: The intraclass correlation coefficient (ICC) is most appropriately used in orthotic research to assess:
- Association between categorical variables
- Test-retest or interrater reliability of continuous measurements (Correct answer)
- Differences in proportions between two groups
- Relative risk of adverse events with orthotic use
Correct answer: Test-retest or interrater reliability of continuous measurements
ICC evaluates the consistency or reproducibility of continuous measurements across raters or repeated assessments.
Question 6: Publication bias in orthotic research literature refers to the tendency for:
- Researchers to publish only studies with complex statistical methods
- Journals to preferentially publish studies with positive or significant results (Correct answer)
- Authors to over-report adverse events associated with orthotic devices
- Peer reviewers to favor studies from academic institutions
Correct answer: Journals to preferentially publish studies with positive or significant results
Publication bias skews the literature because studies with statistically significant results are more likely to be submitted and accepted for publication.
Question 7: In a randomized controlled trial evaluating ankle-foot orthoses, allocation concealment refers to:
- Keeping participants unaware of which orthosis they are wearing
- Preventing those enrolling participants from knowing upcoming group assignments (Correct answer)
- Blinding outcome assessors to group assignment during data collection
- Concealing the study hypothesis from participants until completion
Correct answer: Preventing those enrolling participants from knowing upcoming group assignments
Allocation concealment prevents selection bias by ensuring those recruiting participants cannot predict or influence group assignment.
CFO Research Methods & Evidence-Based Practice 3
In an orthotic outcomes study, a control group receiving a sham orthosis is used primarily to control for: