Quasi-experimental Evidence on Income Tax Return Behavior and the Elasticity of Taxable Income
Abstract
The taxable income elasticity and its decomposition into different responsemargins determine the revenue and efficiency properties of taxation. Exploiting the
German personal income tax allowance threshold as quasi-experimental variation in
tax incentives, this paper provides new bunching-based estimates of a local elasticity
of taxable income in the order of 0.1. The 2007 tax administration data further
allow me to gain insights into the margins behind the response, suggesting that
itemized deductions drive the bunching patterns. For example, I do not find bunching
for taxpayers who forego itemization, while for taxpayers with non-wage income,
itemized deductions account for a sizable proportion of the sharp bunching mass. As
the rules for tax filing, deductibility and enforcement are policy choices, the results
caution against interpreting the elasticity of taxable income as invariant parameter
pinning down optimal tax schedules.