C is for Complexity. This is how complicated, intricate, involved, integrated, etc. the work for a story will involve.
U is for Uncertainty. This facet constitutes the certainty (or lack thereof) for the work that needs to be done. The team may be unfamiliar with the technology or uncertain how a particular element of the story may impact architecture or design.
R is for Risk. This encompasses how dangerous a requested change or enhancement may be to the overall system, design, or architecture.
S is for Scope. Scope is how much work or how far-reaching particular changes are.
E is for Effort. This is what we typically associate with story points. It represents the actual work that’s going to be done, the implementation of the user story.