because the two claims are governed by different causation standards. We recognize the difference in legal standards, but conclude that it is not material to the disposition of this case. While, as noted earlier, the “significant factor” test for the Burk tort claim does not require but-for causation, it imposes much more than some de minimus burden on the plaintiff. It “requir[es] a showing of more than a mere causal link,” in that “a factor may be a cause without being significant.” Elzey v. Forrest, 739 P.2d 999, 1001-02 (Okla.1987). The plaintiff “must do more than show that [age] was only one of many possible factors resulting in his discharge.” Wallace v. Halliburton Co., 850 P.2d 1056, 1059 (Okla.1993); see White v. Am. Airlines, Inc., 915 F.2d 1414, 1419-20 (10th Cir.1990) (<HOLDING>). It is not necessary to set out our evaluation
recognizing that court need not address each hahn factor if defendant does not raise issue relating to that factor holding trial court erred by instructing jury that employer would be liable under burk if plaintiff showed improper motive was a factor in the decision to discharge him rather than a significant factor holding that if the plaintiff makes out a prima facie case of age discrimination the employer must show that the discharge was based on reasonable factors other than age  and if the employer meets that burden the plaintiff must show that age was a determining factor in the discharge holding that trial court erred by instructing jury regarding sudden emergency holding that a plaintiff need only show that the results of a polygraph examination were a factor in the termination of employment and rejecting requirement that results be the sole factor for employees discharge