discuss and resolve issues with this test. I think it's fair to say that we have reached an understanding that conceptually the PTI test is acceptable and that the main question that needs resolution is the acceptance criteria to be used with the test.
Now, let's talk about the gap which is really about the sameness or comparisons between the PTI test and the FDA draft guidance test. But first, let me go through a generic operating characteristic curve.
We have here probability to accept as the y axis and some batch variability measure along the x axis, so that we have low variability here and high variability here. So for low variability, that is really the producer protection region, and I should say that this curve here traces the probability that the sample obtained from a batch of the corresponding batch variability is within the specified acceptance limits. So it's the ability of the batch to provide a sample within the limits that makes up this curve.
So in the producer protection region, ideally, the acceptance probability should be a 100 percent for good quality and deviations from a 100 percent. That is