Whether federal courts must defer to an agency's reasonable interpretation of that agency's own regulations (commonly referred to as "Auer deference"), as the Court of Appeals did here with respect to a claim by Hospital, a rural, non-profit acute care hospital, for a "volume-decrease adjustment" provided for under the Medicare statute, 42 U.S.C. §1395ww(d)(5)(D)(ii), and regulations promulgated by the Secretary of Health & Human Services ("Secretary"), 42 C.F.R. § 412.92(e)(3).

Whether federal courts must defer to an agency's reasonable interpretation of its own regulations under the Auer deference doctrine