Three Quirks of the INVEST Model

Bill Wake invented the INVEST acronym to help us remember guidelines for writing effective user stories: Independent, Negotiable, Valuable, Estimable, Small, and Testable. If a story can check these six boxes, it is universally accepted as a good user story.

Each of these properties bring their own set of challenges. In this article, we’ll look at some quirks of the model and get clarity on common misconceptions surrounding it.

Small

What is small? The Scrum guide tells us a story should be able to be finished within a sprint. But no self respecting team would call a story that takes up an entire sprint ‘small’. As small as possible? You run the risk of losing value when you trim everything off a story just to make it very small.

A technique called ‘goldplating’ can help here. Do the simplest thing that works — then stop. We should also keep the pie analogy in mind. We’re building a pie — slice by slice, not layer by layer. This verticality ties in with the ‘independent” checkbox as it makes sure all stories add value by themselves.

So stories should be as small as they can be, while still adding value and including…