in Behavioral Science

The Behavioral Economics of Hospital Acquired Infections (HAI)

According to the CDC, hospital acquired infections (HAI) in the US is a $35 billion problem infecting 1.7 million while killing roughly 99,000 people each year. In other words, HAI kills more people than breast cancer and prostate cancer combined. The main culprit leading to incidences of HAI is doctors and other healthcare providers forgetting or refusing to wash their hands. The reason for these failures may be explained using behavioral economic notions prospect theory, mental accounting, and decoupling effects that lead to hyperbolic discounting.

Prospect Theory

First, consider that each time healthcare providers wash their hands a transaction cost is incurred. In essence, the current system is set to disaggregate losses and aggregate gains (which is not a happy combination). As a result, this system is not optimized to produce the intended effect of compliance. In addition, all things equal, the marginal benefit of each subsequent hand wash can be minimal or even negative. A snapshot of the hand-washing utility model below shows how utility is negative after the first hand-washing using anti-microbial soap that kills 99.9% of germs against a microbe that replicates itself every 15 minutes. Note: Putting more weight to costs (losses) may produce a more accurate graph.

Hand-washing Utility Model
X-axis: Number of hand-washings
Y-axis: Utility

Mental Accounting

Infection control at hospitals is a serious matter. According to the World Health Organization (2002), infection control protocols call for several preventative measures such as hand-hygiene, use of surgical drapes, cold temperatures in operating rooms, minimizing operating times and length of hospital stay, and the use of anti-microbial prophylaxes. It isn’t too difficult to imagine that physicians may bundle all infection control protocol costs into one mental account. If so, this phenomenon may explain why physicians may abstain from hand washing. Instead of paying the immediate costs1 related to hand-washing efforts, physicians may be balancing costs in the infection control account by thinking other measures such as prescribing prophylaxes will cover the costs. In the cases described, decisions are being made piecemeal and are topical suggesting the use of a mental account.

Hyperbolic Discounting

            Moreover, the effects of not washing your hands are not as immediate as, say, the effect of ‘forgetting’2 to use anesthesia. Thus, not washing hands becomes decoupled from the costs of future outbreaks. In turn, this effect reduces the salience of the outcome. Likewise, the perception of future benefits from washing hands is also minimized due to hyperbolic discounting.

1’Immediate costs’ or ‘immediate benefits’ do not account for future cost or benefits related to present hand-hygiene performance.

2Although ‘forgetting’ indicates an action outside of the decision-making process, it is used here to mean physicians are deciding not to remember as frequently as they could.


Kahneman, D., & Tversky, A. (1979). Prospect theory: An analysis of decision under risk. Econometrica, 47(2), 263-292.

Thaler, R. H. (1999). Mental accounting matters. Journal of Behavioral Decision Making, 12(3), 183-206. doi:10.1002/(SICI)1099-0771(199909)12:33.0.CO;2-F

World Health Organization. (2002, December). Prevention of Hospital-acquired Infections A Practical Guide (World Health Organization, Department of Communicable Disease, Surveillance and Response). Retrieved from