In 2014, the British government undertook a national experiment with the report card approach-sending letters to thousands of doctors in England who were prescribing the most antibiotics per capita in their regions. The letters, from high-profile British leaders, let those doctors know that they were prescribing more antibiotics than 80 percent of their local peers and suggested alternatives to writing a prescription in the heat of the moment, such as giving patients advice to care for themselves while sick. Researchers from the UK government’s Behavioural Insights Team found that these letters corresponded with a substantial decline in the rate of antibiotic prescription, with an estimated seventy thousand fewer antibiotics given to patients in a six-month period. The letters had cost very little, but they had saved significant sums of money spent on medicine by the national health care system and protected public health.
Recently, the Behavioural Insights Team began altering the letter sent to British citizens if they failed to pay taxes on their car. The traditional letter was all text, informing the subject that if they didn’t pay now they would be hit with various penalties, including a clamped or and hefty fines. To increase the effectiveness of the letter, the scientists began experimenting with various forms of personalization. The first variant involved making a more specific threat, telling recipients that they would lose their particular model of car if they didn’t pay the tax. The second variant featured a personalized visual, so that the letter came attached with a photograph of the actual car question. While both approaches increased compliance, the customized picture was the most effective—it increased the compliance rate from 40 to 49 percent.