So we've already heard talk about the limiting quality; that is, defining the batch that anyone would agree is an unacceptable batch, but we somehow need to define an additional value which is the quality, the level of quality that corresponds to, if that's routinely accepted, that's a good thing.
I might point out, also, say I have a process that produces a standard deviation of 13. Well, now, with that process, the FDA test is going to be accepting fewer than 50 percent of my batches. Similarly, the parametric test is only going to be accepting about 62-63 percent of my batches. So in either case, I'm in trouble, but this curve, this blue curve is for the proposed test with 12 in the first tier and an additional 24 if you go to the second tier, but if I increase my sample size, I can make the operating characteristic curve for the proposed test go higher and by taking a large enough sample size, I can make it go higher than 90.
So the issue that is currently occupying our attention in CDER is whether we need to specify this additional level of quality to be assured and how can that be done.