But , one of the reasons I have Chuck 's messing around with  with the back - end that you 're not supposed to touch  I mean , for the evaluations , yes , we 'll run a version that hasn't been touched.
Mm - hmm. Mm - hmm.
But , uh , one of the reasons I have him messing around with that , because I think it 's sort of an open question that we don't know the answer to. People always say very glibly  that i if you s show improvement on a bad system , that doesn't mean anything , cuz it may not be   show  uh , because , you know , it doesn't tell you anything about the good system.
Mm - hmm.