Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
We show that the introduction of information reporting for charitable tax deductions in Denmark in 2008 was associated with a doubling in the number of deductions claimed, and a 15% rise in the total value of claims, which can be credibly attributed to previously unclaimed deductions. This contradicts the presumption that evasion is the main source of non-compliance for deductions, and that the use of information reporting raises revenue collections. A pre-reform randomized audit experiment did not detect the unclaimed deductions, implying audits overstate evasion relative to extensive-margin underreporting. Various tests suggest that compliance cost, passive choice and overwithholding suppressed self-reporting of deductions.