Measuring Explicit Tax (Dis)Advantage for Corporate Taxpayers: An Alternative to Average Effective Tax Rates.

Studies using the average effective tax rate (ETR) to measure corporate tax (dis)advantage have played a critical role in tax legislation. Recent research, however, has questioned the effectiveness of the ETR for this purpose. In this study we extend that line of research in two ways. First, we assess the availability and reliability of the ETR as a measure of tax (dis)advantage. Second, we develop an alternative statistic to the ETR. We empirically test the alternative statistic against the ETR in a replication of the U.S. General Accounting Office study of the effect of the 1986 Tax Reform Act on corporate tax (dis)advantage. Our empirical results indicate that the ETR is often unavailable, and when it is available, it is not reliable as an indicator of cross-firm and through-time differences in tax (dis)advantage. Further, we show that a more direct measure of tax (dis)advantage, the tax subsidy on equity statistic (TSE), can be computed for almost all firm-years and is belier able to identify firms that are more or less tax-advantaged. These findings should allow policymakers to enact more effective legislation and enable researchers to construct experiments that have greater power and more internal validity.