I’m conducting retrospective validation report and the statistic as tools I chose are “control chart” and “CpK”
But my factory advisor recommend me that CpK should use if the parameter is continuous such as filling voulme of product, but my parameter for 20 batches are pH, Assay, specific gravity which are individual in each batch.
So, i’m not sure i can use Cpk as a tool for my project? Plese help me T_T
Interesting question. We recently had the same discussion but slightly different. The ME’s were attempting to measure Ppk (not taken in order) on individual vials coming from the same batch. I didn’t think it was a good idea. If it were fill volumes I would agree but not individual readings of chemical properties taken from the same batch.
Now taking readings from different batches I could see where it may be more appropriate. Even in this case I would want to monitor the process taking samples batch-to-batch rather than attempt to measure capability. I see you getting into some trouble where you will have a tough time coming up with an explanation.
Posted by Bruce Tive
yessss, i’ll have a tough time -*-
Thank you for your kindness, gokeeffe. I do agree with you that Cpk shoud use only if that is the contonuous parameter.
But for other individuals,it’s my task to work hard.
Thank you!!! 
Hi earth.
pH, fill volume, specific gravity, etc. are examples of continuous datasets, so you can calculate process capability. Process capability analysis, along with confidence intervals, would be a good idea I think.
Mike
[quote=earth_ka]I’m conducting retrospective validation report and the statistic as tools I chose are “control chart” and “CpK”
But my factory advisor recommend me that CpK should use if the parameter is continuous such as filling voulme of product, but my parameter for 20 batches are pH, Assay, specific gravity which are individual in each batch.
So, i’m not sure i can use Cpk as a tool for my project? Plese help me T_T[/quote]