CPM-GOMS stands for two things: Cognitive Perceptual Motor and the project planning technique Critical Path Method (from which it borrows some elements).
However, when the tasks are broken down just to the level where they are still perceptual or motor, the evaluator applies techniques from the model human processor.
This technique facilitates representation of overlapping and very efficient "chunks" of activity characteristic of expert users.
Research is currently being conducted to improve the CPM-GOMS technique so that it can be used without the evaluator having a high level understanding of the GOMS theoretical foundations.
Cogulator, an open source software package, can be used to build CPM-GOMS models