Economic studies (unlike say a chemistry studies) suffer from not being able to be done in a lab. Rather they are stuck in the messy real world. In the short-run employers have to keep the store open with the present business model. In the long-run so many things have changed that wage changes is only one of many things going on. I believe that raising a minimum wage will make some jobs go away (or at least accelerate their elimination). Maybe that is okay as a job that pays only $8 might not be a job worth having/existing. Maybe $15 is what is needed to make a living. However maybe there are some jobs and businesses that should exist (and can at $10–12 wage) that can’t exist in the long-run with $15 a hour wage. I don’t have a good answer for this gap between the “ability to pay” and “needed to paid” but I am not surprised their are bumps in the road.