Patient Safety & Quality Improvement USMLE Step 1 Practice Question
A 400-bed teaching hospital implements a new hand hygiene compliance program in July. The hospital epidemiology team uses standardized direct observation methods to assess compliance among all healthcare workers (physicians, nurses, respiratory therapists, and ancillary staff) during routine patient care rounds. Monthly compliance rates are tracked: July 72%, August 75%, September 78%, October 76%, November 79%, and December 80%. The hospital administration presents these data to the board as evidence of successful quality improvement, noting the upward trajectory over 6 months. However, the quality improvement officer notes that the variations between individual months are within expected statistical bounds given the observation sample size. Which of the following statistical concepts best explains why the month-to-month fluctuations may not represent true sustained process improvement?
Answer choices
- ACommon cause variation inherent to the measurement system and natural process performanceCorrect answer
- BSpecial cause variation indicating the intervention has successfully altered the underlying process
- CType II error resulting from insufficient statistical power to detect meaningful improvement
- DHawthorne effect causing temporary behavioral changes that will not be sustained long-term
- EMeasurement bias from observers increasing their surveillance intensity after poor compliance months
- FConfounding from concurrent implementation of automated soap dispensers that improved accessibility
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