The INVEST technique is a set of criteria developed by Bill Wake that Agile and Scrum teams use to ensure that a user story in the product backlog is well-structured and well-understood.
The acronym INVEST stands for Independent, Negotiable, Valuable, Estimable, Small, and Testable, which represents a set of guidelines for creating effective user stories. Here’s a deeper look into each one:
- Independent: The user story should be independent of other stories, meaning it can be developed, tested, and deployed independently. This reduces complexity and avoids prioritization and planning issues that arise when stories are interdependent.
- Negotiable: While the story’s goal or intent is immutable, the details on how to achieve it should be negotiable, whether it’s between the product owner and the team, or the team members themselves. This fosters collaborative decision-making and often results in better solutions.
- Valuable: Each user story must provide value to the end user or customer. The value can be in terms of functionality, performance improvement, business process efficiency, etc. If it’s hard to determine the value of the story, it might be a sign that it needs to be more clearly defined or even that it may not be necessary.
- Estimable: The team should be able to estimate the size or effort needed to complete the user story. If the story is too vague, it may need more details or need to be broken down into smaller stories.
- Small: User stories should be small enough to be coded, tested, and delivered in a single iteration. They should not be so large that they become unwieldy or impossible to estimate accurately. If a story seems too large, it may need to be broken down into smaller, more manageable stories.
- Testable: Finally, a user story should be testable. If it’s not clear how a story can be tested, it may not be well-defined enough. The acceptance criteria that are part of a user story are key to understanding how to test it.
The goal of using the INVEST technique is to create a clear, understandable user story that can be easily estimated and implemented by the team, providing value to the customer or end user.
