I'll be giving a talk at the American Society for Andrology in April about the use of quality control for sperm morphology assessments. I'll put some of my notes up on the web when I get the chance. The National Institute of Standards and Technology has a nice engineering statistics handbook with a whole chapter on process or product monitoring and control.
Sperm morphology is a classification system. I've found that the concept of entropy is useful in understanding ambiguities in classification systems, and I've started a web page about entropy.
You can find an earlier version of this page on my original website.