INVEST (mnemonic)
The INVEST mnemonic for Agile software development projects was created by Bill Wake as a reminder of the characteristics of a good quality Product Backlog Item (commonly written in user story format, but not required to be) or PBI for short. Such PBIs may be used in a Scrum backlog, Kanban board or XP project.
| Letter | Meaning | Description |
|---|---|---|
| I | Independent | The PBI should be self-contained. |
| N | Negotiable | Draft PBIs are not explicit contracts and should leave space for discussion. |
| V | Valuable | A PBI must deliver value to the stakeholders. |
| E | Estimable | You must always be able to estimate the size of a PBI. |
| S | Small | PBIs should not be so big as to become impossible to plan/task/order within a level of accuracy. |
| T | Testable | The PBI or its related description must provide the necessary information to make test development possible. |