must “constitute! ] a significant change in employment status, such as hiring, firing, failing to promote, reassignment with significantly different responsibilities, or a negative performance evaluations alone can constitute an adverse employment action .... [Plaintiff] has not identified, nor have we discovered, a single case where adverse performance ratings alone were found to constitute adverse action.” Smart v. Ball State Univ., 89 F.3d 437, 442 (7th Cir.1996). An isolated threat or proposal of a potentially adverse action is not, in and of itself, materially adverse. See Wells v. Colo. Dep’t of Transp., 325 F.3d at 1214. The threat of being written up for insubordination is not enough to establish an adverse employment action. See Sanchez v. Denver Pub. Schs., 164 F.3d at 533 (<HOLDING>). In support of this conclusion, the Tenth
holding that unsubstantiated oral reprimands do not constitute an adverse em ployment action absent evidence that they had some impact on the employees employment status holding that an employees unsubstantiated testimony that he was better qualified than employees that were not subject to adverse employment actions was insufficient to defeat summary judgment recognizing that a set of actions may constitute an adverse employment action when considered collectively even though some actions do not rise to the level of an adverse employment action individually holding that poor evaluations alone do not constitute an adverse employment action holding that written reprimands with only speculative consequences do not constitute adverse actions