From the NY Times. You can always find examples of misclassification when you apply a discrimination function: A mispriced insurance risk, an unfair speeding ticket, a student penalized because of poor handwriting. What is important is to have clear channels of redress. If a teacher thinks their ranking is unfair, they should by all means make the case to change it.
Note how that doesn’t happen when the rankings aren’t part of the evaluation. If the rankings don’t matter then teachers have no reason to correct them and they don’t mean anything. In other words, it isn’t a ranking at all if there are no consequences.