Validate

Verification asks whether the work matches what was asked. Validation asks whether what was asked was right. It is the only check in the process able to find that the criteria themselves were wrong — every gate before it inherits the assumption that they were correct.

Its object is the outcome, not the work. A passing specification proves the system does what was written down. It cannot prove that what was written down was what the persona actually needed, because a missing criterion leaves no trace among the criteria that remain.

Validation is held as close to the persona as the system allows. The persona itself is the strongest form. Where that is not possible — and often it will not be — whoever stands in for them is recorded as having done so, exactly as an unheld role is recorded rather than quietly filled.

A failed validation sends the work further back than a failed verification. A failed verification returns the thing that was produced. A failed validation says the criteria were wrong, so the item returns to Specify — there is nothing wrong with the change.

Not everything can be validated. A chore changes no capability, so there is no outcome for anyone to judge; it travels on its verifications alone. Validation applies wherever there is an outcome somebody was meant to receive.

Validation needs something the persona can actually use. How that is arranged — a preview, a staged environment, a limited release — is an application matter; the practice requires only that what they judge is the real outcome and not a description of it.

Done when: the outcome has been judged by the party it was for, or by a recorded stand-in.