From Taproot Administrative Servs. v. Comm’r of Internal Revenue, 133 T.C. 202, 2009 U.S. Tax Ct. LEXIS 29, 133 T.C. No. 9 (U.S. Tax Court Sept. 29, 2009):

In United States v. Mead Corp., 533 U.S. 218, 121 S. Ct. 2164, 150 L. Ed. 2d 292 (2001), the Supreme Court recognized that there are various types of agency pronouncements that may be entitled to differing levels of deference and that the lowest level of deference — Skidmore deference — has continuing vitality. See id. at 234 ("Chevron did nothing to eliminate Skidmore's holding that an agency's interpretation may merit some deference whatever its form, given the 'specialized experience and broader investigations and information' available to the agency" (quoting Skidmore v. Swift & Co., 323 U.S. 134, 139, 65 S. Ct. 161, 89 L. Ed. 124 (1944)); id. at 235 (concluding that a tariff classification ruling by the U.S. Customs Service "may surely claim the merit of its writer's thoroughness, logic, and expertness, its fit with prior interpretations, and any other sources of weight"). In so doing, the Supreme Court set forth a two-prong test for determining whether to afford an agency pronouncement Chevron deference. Id. at 226-227 ("We hold that administrative implementation of a particular statutory provision qualifies for Chevron deference when it appears that Congress delegated authority to the agency generally to make rules carrying the force of law, and that the agency interpretation claiming deference was promulgated in the exercise of that authority."); see also Marmolejo-Campos v. Holder, 558 F.3d 903, 908 (9th Cir. 2009) (en banc) ("Not every agency interpretation of its governing statute is entitled to Chevron deference, however.").