From Graff v. Town of Pembroke, NH, 447 B.R. 51, 2011 Bankr. LEXIS 783 (Bankr. D.N.H. 2011):

Federal courts traditionally looked to three factors in determining whether a current decision in a civil case should be given retroactive effect or only apply prospectively. Those factors are: (1) whether the more recent rule or decision establishes a new principle of law, either by overruling clear past precedent on which litigants may have relied, or by deciding an issue of first impression whose resolution was not clearly foreshadowed; (2) whether, given the history, purpose and effect of the new rule, retroactive application of the rule will further or retard its operation; and (3) whether retroactive application of the new rule could produce substantial inequitable results. Northern Pipeline Constr. Co. v. Marathon Pipe Line Co., 458 U.S. 50, 87-88, 102 S. Ct. 2858, 73 L. Ed. 2d 598 (1982) (citing Chevron Oil Co. v. Huson, 404 U.S. 97, 106-07, 92 S. Ct. 349, 30 L. Ed. 2d 296 (1971)). The standard in Chevron has evolved in a number of ways which leave little clarity for courts to follow. Educ. Credit Mgmt. Corp. v. Mersmann (In re Mersmann), 505 F.3d 1033, 1051 (10th Cir. 2007). Chevron has been described as being overruled by the decision in Harper v. Virginia Dep't of Tax'n, 509 U.S. 86, 97, 113 S. Ct. 2510, 125 L. Ed. 2d 74 (1993). Reynoldsville Casket Co. v. Hyde, 514 U.S. 749, 752, 115 S. Ct. 1745, 131 L. Ed. 2d 820 (1995); Mills v. Maine, 118 F.3d 37, 49 (1st Cir. 1997). The application of a federal law to a particular case does not turn on "whether litigants actually relied on an old rule or how they would suffer from retroactive application of a new one." Mersmann, 505 F.3d at 1051-52 (citing Harper, 509 U.S. at 95 n.9). However, equitable principles govern the exercise of bankruptcy jurisdiction. Mersmann, 505 F.3d at 1052; In re Jarvis, 53 F.3d 416, 419 (1st Cir. 1995) (citing Pioneer Inv. Servs. Co. v. Brunswick Assocs. Ltd. P'ship, 507 U.S. 380, 389, 113 S. Ct. 1489, 123 L. Ed. 2d 74 (1993)); In re Smith Corset Shops, Inc., 696 F.2d 971, 976 (1st Cir. 1982) (citing Bank of Marin v. England, 385 U.S. 99, 87 S. Ct. 274, 17 L. Ed. 2d 197 (1966)).