The Definition of Done (DoD) enables a team to understand what things must happen to a Product Backlog Item (PBI) for it to be considered complete (done). The DoD is a list of statements (quite possibly a check list) that defines the actions and states what must be successfully completed to each PBI in the sprint, e.g. all code must be code reviewed, relevant documentation has been created, all tests are passing and test coverage hasn’t decreased.
The DoD is used to aid transparency with the team and especially with the Product Owner as there is a shared understanding that all items are completed to the same level of detail regardless of who has worked on it. It can be used by team members to have an open discussion with other team members when reviewing the work and ensuring that the quality is at the sufficient level.
The DoD is also used in Sprint Planning by the Development Team, as they select the number of Product Backlog Items based on completing the work all the way to “Done”.
Ideally there would be a departmental DoD that all development follows, but at the very least there should be a per team DoD.
As teams mature within Scrum, the DoD is revisited and altered as what once were uncommon practice, e.g. code reviews, documentation, become second nature and the team wants to improve the quality of the product further, they add additional steps.
The Sprint Retrospective is the formal opportunity to improve the quality of the DoD, however this can be done at any time within Sprint if the team feel it is appropriate. The quality level of the DoD (i.e. the steps covered)can NEVER be reduced, this would lead to uncertainty and increased risk in the Sprint.
The DoD is not the same as Acceptance Criteria in the PBI’s as these are specific to individual PBI’s