Objective: To assess the clarity and efficacy of the World Health Organization (WHO) hand-rub diagram, develop a modified version, and compare the 2 diagrams. Design: Randomized group design preceded by controlled observation and iterative product redesigns. Setting: The Cognitive Ergonomics Lab in the School of Psychology at the Georgia Institute of Technology. Participants: We included participants who were unfamiliar with the WHO hand-rub diagram (convenience sampling) to ensure that performance was based on the diagram and not, for example, on prior experience. Methods: We iterated through the steps of a human factors design procedure: (1) Participants simulated hand hygiene using ultraviolet (UV) absorbent lotion and a hand-rub technique diagram (ie, WHO or a redesign). (2) Coverage, confusion judgments, and behavioral videos informed potentially improved diagrams. And (3) the redesigned diagrams were compared with the WHO version in a randomized group design. Coverage was assessed across 72 hand areas from multiple UV photographs. Results: The WHO diagram led to multiple omissions in hand-surface coverage, including inadequate coverage by up to 75% of participants for the ulnar edge. The redesigns improved coverage significantly overall and often substantially. Conclusions: Human factors modification to the WHO diagram reduced inadequate coverage for naïve users. Implementation of an improved diagram should help in the prevention of healthcare-associated infections.

Motivation: Hand hygiene is essential in reducing the spread of infectious diseases; the hands of healthcare workers are a common critical intermediary in the transfer of pathogens from patient to patient (Allegranzi & Pittet, 2009; Boyce & Pittet, 2002). The widely used World Health Organization's (WHO) hand-rub standard, virtually identical to the European standard (EN1500) and related to the US CDC's (3-step diagram), has been studied and compared to other diagrams (Reilly et al., 2016). Literature shows that the current standards for hand hygiene do not cover hands of healthcare workers adequately (Skodova et al., 2015; Szilágyi et al., 2013). The goal of the current study was to evaluate and modify the WHO diagram using human factors approaches like behavioral videos, confusion reports, and coverage data to improve coverage of all hand surfaces.