How mobile text reminders earned Madagascar a 32,900% ROI in collecting unpaid taxes

We took a group of 15,885 late-income-tax filers and randomly assigned some of them to receive a series of messages reminding them to file a tax declaration and emphasizing various reasons to pay taxes. Late tax filers were told that they could avoid a late penalty by meeting an extended deadline and were given the link to the tax filing website.

The results of the experiment were significant. In the control group, only 7.2% of late filers filed a tax return by the extended deadline cited in the SMS messages. This increased to 9.8% in the treatment groups who received SMS reminders. This might not sound like much, but for every dollar spent sending text messages, the tax authority collected an additional 329 dollars in revenues, making the intervention highly cost-effective.

In fact, the return on this particular investment was 32,900 percent! Although this increase in revenue is relatively small in absolute terms—around $375,000—it could be automatically integrated into the tax system. It also suggests that messaging may hold a lot of promise for cost-effectively increasing tax receipts even in developing country contexts.