INVEST is an acronym that stands for Independent, Negotiable, Valuable,Estimable, Small, and Testable12. It is a set of criteria used to assess the quality of a user story in Agile methodologies12. Here’s what each term means:
Independent: The user story should be self-contained, in a way that there is no inherent dependency on another user story12.
Negotiable: User stories, up until they are part of an iteration, can always be changed and rewritten12.
Valuable: A user story must deliver value to the end user12.
Estimable: You must always be able to estimate the size ofa user story12.
Small: User stories should not be so big as to become impossible to plan/task/prioritize with a certain level of certainty12.
Testable: The user story or its related description must provide the necessary information to make test development possible12. References: 12