Several examples exist to suggest that labeling people often hits the wrong note and ends up disrupting work. People underperform when they are categorized. This is especially true when someone is labeled as a ‘low performer’. Such categorizations also limit employee engagement. A case where exceptional talent management by a senior professor helped one of his students was when a student who was supposed to be a “big picture” personality and thus not suited to “detail oriented” sessions was motivated when his attention to detail while composing music was highlighted and appreciated. Similarly, a manager who was to assemble a cross-functional team ended up with only “mediocre” or “poor” performers from other departments ended up getting the best out of these same employees once these categories had been taken off their backs.

Source: https://hbr.org/2016/09/why-you-shouldnt-label-people-low-performers