352 Hand hygiene is accepted throughout the health care community as a basic clinical procedure essential for the prevention of infections in patients and health care workers (HCWs) alike. 1 However, studies consis- tently show that HCWs practice hand hygiene incom- pletely and infrequently, with rates of adherence to guidelines often lower than 70%. 2 Although the hand hygiene procedure itself is simple, HCW behavior relat- ed to hand hygiene is a complex phenomenon that is not easily understood, explained, or changed. Knowledge about when, why, and how HCWs should practice hand hygiene is widely available. According to current guidelines from the Association for Professionals in Infection Control, HCWs should prac- tice hand hygiene when their hands are visibly soiled, before and after patient contact, after contact with body secretions or excretions or inanimate objects like- ly contaminated, and after removing gloves. 3 Appropriate technique includes use of soap and water. The hand hygiene agent should be distributed to all hand surfaces, and hands should be rubbed vigor- ously for 10 to 15 seconds. An alcohol-based handrub may be used instead of soap and water if the hands are free of organic soiling. Knowledge about hand hygiene, awareness of per- sonal handwashing practices, types of hand hygiene products, and accessibility of supplies have all been recognized as factors that may influence HCW adher- ence to hand hygiene recommendations. Education and training, the most frequently implemented inter- ventions designed to improve adherence, have had lim- Understanding adherence to hand hygiene recommendations: The theory of planned behavior Carol A. O’Boyle, PhD, RN a Susan J. Henly, PhD, RN b Elaine Larson, PhD, RN, FAAN c Minneapolis, Minnesota, and New York, New York Background: Most health care workers (HCWs) are aware of the rationale for hand hygiene procedures, yet failure to adhere to guidelines is com- mon. Little is known about factors that motivate HCWs to practice hand hygiene. Purpose: The purposes of this study were to (1) estimate adherence to hand hygiene recommendations; (2) describe relationships among motivation- al factors, adherence, and intensity of nursing unit activity; and (3) test an explanatory model for adherence to hand hygiene guidelines based on the theory of planned behavior (TPB). Method: A longitudinal, observational design was used to collect data from 120 registered nurses employed in critical care and postcritical care units. Nurses provided information about motivational factors and intentions and a self-report of the proportion of time they followed guidelines. At least 2 weeks later, the nurses’ hand hygiene performance was observed while they provided patient care. Structural equation modeling was used to test the TPB-based model. Results: Rate of adherence to recommendations for 1248 hand hygiene indications was 70%. The correlation between self-reported and observed adherence to handwashing recommendations was low (r = 0.21). TPB variables predicted intention to handwash, and intention was related to self- reported hand hygiene. Intensity of activity in the nursing unit, rather than TPB variables, predicted observed adherence to hand hygiene recommen- dations. Conclusions: The limited association between self-reported and observed hand hygiene scores remains an enigma to be explained. Actual hand hygiene behavior may be more sensitive to the intensity of work activity in the clinical setting than to internal motivational factors. (Am J Infect Control 2001;29:352-60.) From the Division of Disease Prevention and Control, Minnesota Department of Health a ; the School of Nursing, University of Minnesota, Minneapolis b ; and the School of Nursing, Columbia University, New York. c Portions of this paper were presented at the 1998 annual meet- ing of the Association for Professionals in Infection Control in Baltimore, Md. Supported in part by grants from the Georgetown University School of Nursing, the 3M Enrich Program, and the Association of Professionals in Infection Control Research Foundation. Reprint requests: Carol A. O’Boyle, PhD, RN, Assistant Professor, School of Nursing, 6-101 Weaver-Densford Hall, University of Minnesota, 308 Harvard St, SE, Minneapolis, MN 55455-0342. Copyright © 2001 by the Association for Professionals in Infection Control and Epidemiology, Inc. 0196-6553/2001/$35.00 + 0 17/46/118405 doi:10.1067/mic.2001.118405