How to Split User Stories: Techniques and Best Practices

User story splitting is a daily practice for agile delivery teams, but it can be challenging; this article consolidates everything the author has learned about story splitting.

The author defines a user story as a unit of scope and delivery, emphasizing that stories convey useful information to others, typically system users or stakeholders.

Two subtle scenarios exist for the term "user story": one representing the scope unit itself, and the other describing that scope unit using the "As ... I can ... so that ..." format.

1.1 User Story Attributes and the INVEST Criteria

Independent – not dependent on other stories

Negotiable – can be discussed and changed

Valuable – provides value to stakeholders

Estimable – clear enough for the team to estimate effort

Small – small enough to deliver multiple stories in a sprint

Testable – can be verified through testing

In practice, splitting stories to make them "small enough" often introduces dependencies, and a single story may not have value on its own; only a set of related stories delivers value.

2. Why Split Stories?

Splitting stories makes them small enough to be delivered within a sprint, aligning with the Pareto principle (80/20 rule) to separate high‑value work from low‑value, high‑effort tasks, allowing low‑value items to fall to the bottom of the backlog.

3. Story Levels and Epics

Large stories are called epics; epics may need multiple splits to reach a size suitable for the development team. Story hierarchy can have many levels and is not fixed.

4. How Small Should Stories Be?

The appropriate size depends on the team and sprint length; small stories improve efficiency, motivation, and resource planning.

5. When to Split Stories

Stories should be split Just‑In‑Time, after sufficient analysis to understand the story.

5.1 Initial Analysis (BADM)

The Business Analysis Designer Method (BADM) provides a structured analysis process with stages: Request, Define, Design.

6. Vertical Story Slicing

Vertical slicing ensures each story delivers user‑visible value across all architectural layers, avoiding horizontal splits that delay user value and testing.

7. User Goal Decomposition

Decompose user goals into sub‑goals, creating sub‑stories that each deliver a piece of the overall objective.

8. Three Named Goal Levels

Cockburn's model defines User Goal (sea‑level), Summary Goal (cloud‑level), and Sub‑function Goal (underwater‑level) to help track value.

9. Story Splitting Order

Various techniques are applied in a typical order, though not rigidly.

10. Story Splitting Techniques

Technique 1: Split NFRs – separate functional work from non‑functional requirements.

Technique 2: Split by UI Channel – focus on one platform or device first.

Technique 3: Split by User Type – prioritize user segments.

Technique 4: Split Summary Goals into User Goals – break down high‑level goals.

Technique 5: Split by Scenario/Flow – separate happy path from alternative flows.

Technique 6: Copper vs. Gold – implement a minimal viable version before polishing.

Technique 7: Step‑by‑Step – build a skeleton and fill in details.

Technique 999: Spike – use exploratory work when size or architecture is uncertain, but beware of scope creep.

11. Story Splitting Is Hard

Splitting stories is complex and iterative; there is no fixed hierarchy, and the right size depends on team satisfaction.

12. Conclusion

Split stories to separate high‑value from low‑value work.

Story splitting is iterative; fixed hierarchies are meaningless.

Story size depends on team comfort.

Split Just‑In‑Time after sufficient analysis.

Use vertical slicing to break user goals into sub‑goals.

Cockburn's goal levels help track progress.

Many techniques exist; apply them in a logical order.

Story splitting is difficult, but perseverance pays off.

References

Bill Wake – "Twenty Ways to Split Stories"

Richard Lawrence – 80/20 rule and story patterns

Mike Cohn – "You Don't Need a Complicated Story Hierarchy"

Rachel Davies – story slicing ideas

Alistair Cockburn – Effective Use Cases

Lynda Girvan & Debra Paul – Agile and Business Analysis

Christiaan Verwijs – Vertical Story Slicing