SAFe PI Planning Principle
Stories should be sized to fit within a single iteration. SAFe recommends stories of
8 points or fewer — anything larger typically contains hidden complexity
or multiple independently deliverable slices. Stories this size rarely meet the
Definition of Done within one sprint and create carry-over risk.
Vertical slicing techniques
1
Slice by workflow step
Break the story along the user's journey — one story per distinct step a user takes to achieve their goal. Each slice delivers a working, testable increment.
2
Slice by business rule or scenario
Implement the happy path first as one story, then edge cases and business rules as separate stories. All share the same AC framework.
3
Slice by data variation
If the story handles multiple data types, sources, or personas differently — each variation can be a separate story with its own AC and acceptance criteria.
4
Spike + implementation
If the high estimate reflects unknowns, create a time-boxed spike story (2–3 pts) to investigate, then a separate implementation story once the approach is clear.
Good vertical slice test: Each slice should be independently deployable, provide direct user value, and be completable within one iteration without dependency on the other slices.