Experimental pretesting of hand-washing interventions in a natural setting

The investigators pretested interventions derived from different domains of behavior change theory to determine their effectiveness at increasing handwashing with soap in a natural setting. They installed wireless devices in highway service station restrooms to record entry and soap use. Two text-only messages for each of 7 psychological domains were compared for their effect on soap-use rates. They collected data on nearly 200, 000 restroom uses. The knowledge activation domain was most effective for women, with a relative increase in soap use of 9.4% compared with the control condition. For men, disgust was the most effective, increasing soap use by 9.8%. Disgust was not significantly better than the control condition for women, nor was knowledge activation for men. Messages based on social norms and social status were effective for both genders. Am J Public Health. 2009;99 Suppl 2:S405-11.