User stories are reminders of features, not full specifications. Avoid recording every detail up front because details change. We’ll capture the details later, when they matter.
When a story reads like a contract, it stops being a conversation. When it reads like a reminder, it invites one.
Follow the acronym “INVEST” as a quick check.
- I.NDEPENDENT
- N.EGOTIABLE
- V.ALUABLE
- E.STIMATABLE
- S.MALL
- T.ESTABLE
ESTIMATABLE
Stories must be concrete enough to estimate. Vague demands like “The system must be fast” are not estimable, they lack scope, measurable criteria, and acceptance tests.
Some examples of strategies to make these more concrete are:
- naming the scope (e.g., search API),
- adding measurable targets (e.g., 95th-percentile response < 300ms under X load),
- listing verification steps (load test scenario, observed metrics),
This turns a fuzzy non-functional requirement into a vertical, testable, and estimable story that builders can plan and stakeholders can prioritize.
Discussions for your team
- Do we have some backlog items that read like background requirements, not stories?
- Do we have vague stories that ask for “fast”? Can we specify fast using tests (load, profiling, etc)?