Using the same conceptual framework, Professor Beshears has investigated a public health puzzle: why flu shots, which are enormously beneficial to both individuals and the health-care system, are underutilized, even when offered by employers free of change at on-site clinics. In this case, the barrier is the failure of employees to focus on and prioritize getting a flu shot. Professor Beshears tested the effectiveness of a prompt designed to help people remember to get a flu shot and overcome logistical hurdles. A mailing that asked employees to write down a date and a time for getting their shots increased the vaccination rate by 4.2 percentage points above the rate of the unprompted control group.