Comment by pydry

You're thinking of management.

I'm sure most unions would love performance based pay where union reps decide what constitutes good performance. For some mysterious reason management is as keen on unions exercising their judgement as unions are on management deciding.

Where unions agree policies that treat members as interchangeable (e.g. age based pay) it is usually as a result of a compromise brooked with management who would love to have the latitude to give pay raises to scabs, kiss asses and spies.