China Science

Data from the National Cytology Proficiency Testing Update show that as ofJanuary 31, 2006, 9% of 12,786 examinees failed the test on the first attempt. For the secondattempt, the failure rate among those who had initially failed remained surprisingly similar, 10%,although common sense would dictate that it should be much higher among those who have alreadyfailed the test once and should have lower professional skills. What is the reason for thisremarkable improvement in performance? There is a simple explanation: this is a statisticalphenomenon, known as “regression toward the mean.” Two groups of examinees earn failing scoresduring proficiency testing: those whose skills are really insufficient and those who are competentbut who achieved lower scores due to random variation in the test results. The latter,”misclassified” examinees subsequently “regress” toward the mean during the second test; that is,their test results become more commensurate with their genuine skills. Since the failure rates ofall participants during the first and second attempts were similar, we must assume that the majorityof the examinees who failed on the first attempt fall into the second, misclassified group, andonly a minority have truly insufficient skills.

Nagy,GK
Cytopathology Laboratory, Division of Molecular Medicine, Wadsworth Center,New York State Department of Health, Empire State Plaza, Albany, New York 12201, USA.gkn02@health.state.ny.us

skills　 Testing　 Personal failure cytopathology Test, cytology, digestive