view the evidence presented on the motion in the light most favorable to the opposing party. Anderson, 477 U.S. at 255, 106 S.Ct. 2505. A. ADEA Claim The ADEA prohibits age discrimination in employment against any person over age forty. 29 U.S.C. § 623(a)(1). “Because the prohibition against age discrimination contained in the ADEA is similar in text, tone, and purpose to that contained in Title VII, courts routinely look to law developed under Title VII to guide an inquiry under ADEA.” Brewer v. Quaker State Oil Ref. Corp., 72 F.3d 326, 330 (3d Cir.1995) (reversing summary judgment for the employer). But a plaintiff must show age discrimination was the “but-for” cause of the adverse action. Gross v. FBL Financial Services, Inc., 557 U.S. 167, 129 S.Ct. 2343, 174 L.Ed.2d 119 (2009) (<HOLDING>). The burden-shifting analysis established in
holding that the mixedmotive framework does not apply to retaliation cases under title vii holding that in title vii cases the mixedmotive theory of discrimination is available in cases with circumstantial evidence of discrimination holding that such a theory is viable under title vii holding that title vii and adea causation standards are different holding the title vii mixedmotive theory does not apply to adea claims