INVEST is the acronym for six attributes of a good user story:
- Independent: stories can be prioritized in any order
- Negotiable: User stories can be discussed with the product owner and tradeoffs made based on functionality and cost.
- Valuable: user stories must have a clear value
- Estimable: user stories can be estimated for the amount of work they require
- Small: small user stories (4 to 40 hours of work) are easier to create and test than large user stories;
- Testable: the outcome of the story must be testable