Designing for Behavior Change, 2nd Edition

Chapter 9. Crafting the Intervention: Cue, Reaction, Evaluation

One of the earliest and most powerful demonstrations of behavioral science in government came from the UK’s Behavioural Insights Team. They communicated with people who had tax debts and shared with them the fact that most people do in fact pay their taxes. That encouraged people who hadn’t paid to do so themselves. In other words, they used descriptive norms. The results were clear and powerful: a 5.1 percentage point increase in the payment of liabilities within 23 days.¹

Since then tax compliance, not surprisingly, has been a popular area for applied behavioral science among governments around the world. These efforts are often very low cost and have a long history of success.

One such effort comes from the small, underdeveloped country of Kosovo, where the World Bank’s Mind, Behavior, and Development Unit (eMBeD) and the German Development Agency GIZ helped the country’s tax authority design, implement and evaluate three experimental trials to improve tax reporting and collection.² In the US, many Americans grumble about our taxes and how the government doesn’t need them; in places like Kosovo, low tax revenue means the government struggles to provide basic services to their citizens.

The team tested messages meant to encourage residents to report their tax liabilities—using SMS, email, and physical mail. Within ...