In CMMI, the term “special cause of process variation” is used in place of “assignable cause of process variation” to ensure consistency. Both terms are defined identically. (See “special cause of process variation.”)

1. This glossary is from Appendix C of Technical Report CMU/SEI-2002-TR-004.
2. ® CMMI is registered in the U.S. Patent and Trademark Office by Carnegie Mellon University.