Why didn't it work? The problem I see with seniority based schemes is that they totally fail to take into account degree of preferences. If you have enough seniority to have top dibs when picking shifts, and you marginally prefer the afternoon shift over the morning shift then that's the shift you'll get dibs on. Meanwhile, the less senior worker who have kids and therefore must get the afternoon shift (so they can take their kids to school in the morning) gets shafted. Some sort of system that allows less flexible workers to compensate more flexible worker would solve this.
Like I said it’s been a minute since I looked at the literature. But I think they have a few metrics to test for, including workplace morale, the distribution of how often workers get their preferred allotments, etc. I don’t remember any theory for why it doesn’t work, just that they’ve measured it and (as far as I remember) market based solutions fail on these metrics.
As for seniority rules, I don’t remember reading anything about those, but from my experience, I’m not a huge fan, I think there are better systems, particularly those which are based around consensus. However, given Starbucks’ huge corporate management, I’m guessing that seniority is miles ahead of the system they have now, which is probably management arbitrarily picking which is wide open for abuse such as retaliation. They probably picket seniority because it is very hard for management to abuse it.
