Efficacy of Alcohol-Based Hand Rubs in the Disinfection of Stethoscopes

formed, with 1,582 reports of compliance (64.8%). Unit-based observers performed 1,022 observations and reported a compliance rate of 78%; non-unit-based observers performed 1,421 observations and reported a compliance rate of 55.2% (difference in compliance rates reported by unit-based observers vs non-unit-based observers, 22.8%; P< .001). Similar to the results for the entire cohort, the rate of hand hygiene compliance was significantly higher when it was measured by unit-based observers (odds ratio for the likelihood that unitbased observers would report hand hygiene practice as compliant, 2.87 [95% CI, 2.38-3.45]). In our study cohort, the hand hygiene compliance rates of HCWs were determined to be much higher when observations were conducted by unit-based observers than by nonunit-based observers. Of particular interest, this association was similar when analysis was restricted to 6 units that used both types of observers. Published rates of hand hygiene compliance vary from 5% to 81%. This wide range is attributed to the use of nonstandardized definitions by observers, a lack of detailed descriptions of reporting methods, and observerrelated variables. Of note, comparisons between observations conducted by infection control preventionists who are well known to the staff and by a covert third-party observer (a medical student) revealed a modest difference of 7% in the compliance rate. The difference in compliance rates associated with unitbased observations is unlikely a result of an intentional decision by the observer. This phenomenon of "observer bias" might be related to feelings of allegiance to the unit, and it is logical that observers who gauge the compliance of colleagues are more likely to report observations as compliant than are non-unit-based observers who do not routinely work with the observed HCWs. In contrast to the well-described Hawthorne effect, in which knowledge that a person is observing practice leads to increased compliance, in this situation the observer is familiar with the subjects and their duties, leading to reporting variations. The association between unit affiliation and hand hygiene compliance measurement raises a cautionary note for healthcare centers. Those that use unit-based observers might be overestimating hand hygiene compliance. On the other hand, hospitals that use non-unit-based observers might have less favorable (but possibly more accurate) hand hygiene rates than do hospitals that use unit-based observers. In our study, unit-based observers were more than 2-fold as likely to judge hand hygiene behavior as compliant, compared with the likelihood of non-unit-based observers. Although it was impossible in this study to determine which type of observer measured hand hygiene compliance more accurately, it is clear that measured rates are associated with the unit affiliation of the observer. Because more process data and infection-related outcomes are being made public, hospitals are being held accountable more and more for their hand hygiene practices. More than ever, differences in applied methods and the resulting process measurements need to be recognized and standardized. The unit-based affiliation of the observers should be factored into the analysis and interpretation of hand hygiene compliance data.