CMD Research Methods & Evidence-Based Practice 3 — Questions and Answers
Question 1: A long-term care facility tracks fall rates monthly. The control chart shows a data point 3 standard deviations above the mean. This indicates:
- Common cause variation
- Special cause variation (Correct answer)
- Normal seasonal variation
- Measurement error only
Correct answer: Special cause variation
A data point beyond 3 standard deviations on a control chart signals special cause variation, suggesting an assignable, non-random factor requiring investigation.
Question 2: In an intention-to-treat (ITT) analysis, participants who drop out of a trial are:
- Excluded from the final analysis
- Analyzed in the group to which they were originally assigned (Correct answer)
- Moved to whichever group received actual treatment
- Counted as treatment failures automatically
Correct answer: Analyzed in the group to which they were originally assigned
ITT analysis includes all randomized participants in their original assigned groups regardless of adherence, preserving the benefits of randomization and reducing bias.
Question 3: A CMD notices that a new medication study was funded exclusively by the drug manufacturer. This raises concern about:
- Selection bias
- Attrition bias
- Funding bias (industry bias) (Correct answer)
- Hawthorne effect
Correct answer: Funding bias (industry bias)
Industry-funded studies are systematically more likely to report favorable outcomes, representing a form of funding or publication bias that can distort evidence.
Question 4: Which measure of central tendency is LEAST affected by extreme outliers in a dataset?
- Mean
- Median (Correct answer)
- Mode
- Range
Correct answer: Median
The median represents the middle value and is resistant to skewing by extreme values, making it more robust than the mean in skewed distributions.
Question 5: A CMD implements a new wound care protocol and uses a run chart to track healing rates. Run charts are primarily used to:
- Test for statistical significance between groups
- Display process performance over time (Correct answer)
- Calculate odds ratios for risk factors
- Determine sample size requirements
Correct answer: Display process performance over time
Run charts plot data points sequentially over time to identify trends, shifts, or patterns in a process, supporting ongoing quality monitoring.
Question 6: Confounding in a research study occurs when:
- Participants withdraw before study completion
- A third variable distorts the relationship between exposure and outcome (Correct answer)
- Researchers are aware of participant group assignments
- Outcome measurements are performed inconsistently
Correct answer: A third variable distorts the relationship between exposure and outcome
A confounder is associated with both the exposure and the outcome, creating a spurious or masked association between them if not controlled.
Question 7: The GRADE framework in evidence-based medicine is used to:
- Rank journal impact factors
- Rate the quality of evidence and strength of recommendations (Correct answer)
- Score individual patient risk stratification
- Certify clinical guidelines for regulatory approval
Correct answer: Rate the quality of evidence and strength of recommendations
GRADE (Grading of Recommendations Assessment, Development and Evaluation) systematically assesses evidence quality and translates it into recommendation strength for clinical practice.
CMD Research Methods & Evidence-Based Practice 3
A long-term care facility tracks fall rates monthly.
The control chart shows a data point 3 standard deviations above the mean.
This indicates: