I work for a University and we are fully unionized, so we don't have raises tied to merit or anything- just negotiated annual cost of living increases, maybe 3%? Not sure.
When I was an ed tech (paraprofessional) in the public schools, I was a union negotiator the year Maine put in the new laws increasing minimum wage to $9, $10, and $11 an hour over 3 consecutive years. I'm not talking teachers here, I'm talking staff; para-pros, kitchen staff, janitorial and office staff, etc. It was a nightmare trying to adjust the salary bands. It would have been nice to give everyone the same percentage increase, or the same actual dollar amount increase, but of course that kind of money isn't in the school budget. We finally figured out how to do it, but it included creating more salary bands with a greater number of "steps" so that people who had worked there longest weren't 'out-earned' by those who started at a higher minimum wage. Like I said, it was a nightmare. There was only one band/step that got a crappy increase- just the way it all worked out- and I was on that step; I got a 4cent an hour increase. Sucked, but it was in the best interest of the membership. I guess that makes me a great union rep but terrible in self-interest and support.