Roles and teams
RACI matrix
Also calledDecision rights, Responsibility assignment matrix, RACI chart
A table of decisions against roles that marks who is Responsible, Accountable, Consulted and Informed for each one, so nobody has to guess who decides.
Each cell gets one letter. Responsible: does the work. Accountable: makes the final call and answers for the result. Consulted: asked for input before the decision. Informed: told after it.
The rule that makes it useful is exactly one A per row. Two people accountable for the same decision means nobody is, and a row with no A is a decision that will be made by whoever shouts last.
In practice
A product team marks backlog order and sprint scope as accountable to the product owner, the success metric as accountable to the product manager, and the cross-team schedule as accountable to the technical program manager. The overlap between those three roles, which caused weekly arguments, is now written down.
Common mistake
Filling every cell. A matrix where everyone is consulted on everything slows each decision down and protects nobody.