Can supervisors be guilty of retaliation if they give a mostly positive? Yes, it's possible.
As the following case shows, if an employee views any part of her workplace treatment as retaliation, you're obligated to investigate the complaint. Notify managers not to simply shrug off such seemingly baseless gripes as "oversensitivity."
If the complaint suggests allegations of discrimination against a protected class, handle it according to your anti-harassment policy, regardless of whether any adverse employment action occurred.
Recent case: Cynthia Firestine wasn't shy about expressing her strong Catholic beliefs at the medical office where she worked. In fact, Firestine told her gay supervisor that the Catholic faith didn't approve of a lesbian lifestyle.
Later that year, Firestine received an overall positive job review from that same supervisor, but the review noted a few minor areas for improvement. Firestine reacted angrily, tellingit was a form of religious discrimination because of her previous anti-gay comments.
Soon after, the employer fired Firestine, saying that her comments violated the company policy banning negative comments about co-workers' sexual orientation. Firestine sued, alleging religious discrimination and retaliation.
While a lower court tossed out the case, ruling that a positive job evaluation can't form the basis of a retaliation lawsuit, a federal appeals court let it go to trial. Reason: Firestine's subjective interpretation of the job review was enough proof of discrimination and retaliation. Once she complained that religious discrimination motivated her evaluation, the company had an obligation to investigate it. (Firestine v. Parkview Health System Inc., No. 03-1909, 7th Cir., 2004)