I have to wonder if the restaurants in the study have also attracted new staff as a result of the pay increases ($8 to $13-$15 an hour). New staff may result i

I have to wonder if the restaurants in the study have also attracted new staff as a result of the pay increases ($8 to $13-$15 an hour). New staff may result in those not fully trained (yet), perhaps a small percentage of new staff feel that certain responsibilities are beneath them, new hires may get dumped with more of the "dirty" work, previous staff dismissed in favor of new staff (for various reasons), etc... Just saying that there could be other factors are play here.