The flexibility and ubiquity of the term efficiency in tax analysis can be a double-edged sword. While tax scholars are naturally drawn to the notion of efficiency, with its implied virtues of eliminating waste and of guiding policy choices through objective, non-normative analysis, the danger exists that we can lose sight of which type of efficiency we are talking about when we invoke the concept. What one scholar calls efficient might be quite inefficient under the definition or perspective used by another scholar.
Neil H. Buchanan, The Uses of the Concept of Efficiency in Tax Analysis, 98 Nat'l Tax Ass'n Proc. 441 (2005).