Three Scrum Teams work together on one product. Each has written its own Definition of Done, and they disagree about what "tested" requires. What does Scrum require them to do?

Professional Scrum Master I, objective 1. Understanding and applying the Scrum framework medium

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The options

Correct They must mutually define and comply with the same Definition of Done

Correct. One product means one meaning of Done, and mutually is the operative word — it is agreed between the teams rather than handed to them.

Not correct Each team may keep its own, as long as every one of them is at least as strict as the organisation's standard

Wrong. That still leaves the product's Increments inconsistent with each other, so nobody can say what the combined result of a Sprint actually is.

Not correct The strictest of the three definitions automatically applies to all three teams

Wrong in method even if the outcome sometimes looks similar. Scrum asks the teams to define it mutually, not for the most demanding team to impose its version on the others.

Not correct The Product Owner selects one of the three, since they are accountable for the value of the product

Wrong. The Definition of Done is not the Product Owner's to choose. It is the Increment's commitment and it belongs to the teams building the product.

Why

Everything that keeps multiple teams building one product rather than three lines up here: the same Product Goal, the same Product Backlog, the same Product Owner, and the same Definition of Done. Increments have to be additive across teams and thoroughly verified so they work together, which is impossible if Done means something different depending on who built it.

Where this comes from

Cited
Scrum Guide section Commitment: Definition of Done
What it says
If there are multiple Scrum Teams working together on a product, they must mutually define and comply with the same Definition of Done.

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