It is terribly fragile and ad-hoc. It depends on what you're trying to detect, but the control charts in the OP produce a maddening number of false positives.

It is terribly fragile and ad-hoc. It depends on what you're trying to detect, but the control charts in the OP produce a maddening number of false positives. I had a job that, for about six months, consisted almost entirely of adjusting control limits by hand so the false signal rate would drop.