What is the test for determining whether the rule of law as applied to the facts is or is not violated?

In our view, the key to the resolution of this question is the nature of the inquiry that is required to decide "whether the rule of law as applied to the established facts is or is not violated." Id. If application of the rule of law to the facts requires an inquiry that is "essentially factual," id. at 288, 102 S.Ct. at 1790--one that is founded "on the application of the fact-finding tribunal's experience with the mainsprings of human conduct," Commissioner v. Duberstein, 363 U.S. 278, 289, 80 S.Ct. 1190, 1198, 4 L.Ed.2d 1218 (1960)--the concerns of judicial administration will favor the district court, and the district court's determination should be classified as one of fact reviewable under the clearly erroneous standard. If, on the other hand, the question requires us to consider legal concepts in the mix of fact and law and to exercise judgment about the values that animate legal principles, then the concerns of judicial administration will favor the appellate court, and the question should be classified as one of law and reviewed de novo.