Now as then, disclosure could help to ensure that people pay a fair share of taxes. Americans underpay their taxes by more than $450 billion each year, more than 10 percent of total federal revenue. Publishing a list of millionaires who paid little or no taxes this year could significantly reduce the number of millionaires who pay little or no taxes next year.
In Norway, where tax records have been public since the founding of the modern state in 1814, a newspaper put the records online in 2001. One study estimated that the records’ greater availability caused a 3.1 percent increase in the reported incomes of self-employed Norwegians over the next three years, perhaps because they feared exposure.
Disclosure also could help to reduce disparities in income, as well as disparities in tax payments. Inequality is easier to ignore in the absence of evidence. In Finland, where tax data is published each year on Nov. 1 — jovially known as National Jealousy Day — people treat the information as a barometer of whether inequality is yawning too wide.