Beyond Comprehension: Why Tax Code Complexity Necessitates IRS Deference

This Article argues that deference to Internal Revenue Service (“IRS”) interpretations is essential for the effective interpretation of U.S. federal income tax law due to the technical demands inherent in this uniquely complex area. The U.S. federal income tax code, often considered one of the most intricate legal systems, consists of dense, specialized language, nuanced policy considerations, economic theories, and frequently updated provisions. Judges, as generalists, face a daunting challenge in interpreting this complex, ever-evolving body of law without the specialized expertise that the IRS professionals bring. Frequent amendments further add to this complexity, layering additional provisions that require in-depth knowledge beyond typical judicial training.

To demonstrate the persistent complexity of the Internal Revenue Code (“Code”), even in the wake of significant reform, this Article incorporates an original empirical analysis comparing the 2017 and 2018 versions of the Code using advanced natural language processing techniques. This study confirms that structural and semantic complexity remains deeply embedded in the Code, as evidenced by the lack of a significant reduction following the 2017 Tax Cuts and Jobs Act (“TCJA”). This Article contends that deferring to the IRS’s interpretations is not merely prudent but necessary, as it enables courts to benefit from the agency’s specialized insights, resulting in a more accurate and consistent application of tax law.