IN 2006, according to an estimate by the United States Treasury Department, Americans underpaid their taxes by about $450 billion. For that year, that’s roughly equal to Pentagon spending, and more than the gross domestic products of Sweden and Switzerland.

A good chunk of the missing tax revenues comes from underreporting income, or tax evasion. The rest, roughly 25 percent — about $110 billion — comes from failure to pay taxes, or tax delinquency.

Some people are hard up and can’t afford to pay their taxes. But others simply choose not to pay. When traditional enforcement strategies, like charging above-market interest rates on the debt, don’t work, the government uses a number of tools to collect these taxes. For instance, some states, like Kentucky, can order employers to take a bigger tax bite from the wages of tax delinquents, as allowed by federal and state law.

But traditional collection methods don’t always work. In a recent study, we used another strategy that got results: publicly shaming tax delinquents. It should be a key part of government efforts to increase the collection of tax debts, and thanks to the Internet and social media, the government has the means to make it even more effective.