Ok guys. This one really baffled me. I was in a meeting with our vendor when the program manager said. We can't compute Cpk using GD&T. (I have since convinced most of them that you actually can, thanks to everyone's input.) He then said but we can compute Cp. I have read some previous posts comparing Cp with Cpk. But I can't for the life of me figure out why you can't (or at least they say you can't) compute Cpk but can compute Cp. Are there any differences that would keep you from making the math work.