DIAG-12 · Diagnosis · Invariant — holds by construction, no expiry
Unlogged changes are permanent confounders
The law
For time-based observational attribution, an advertiser-initiated intervention recorded nowhere at execution time can never later be excluded or separated as a confounder: the outcome series maps many-to-one over intervention histories, so unlogged history is unrecoverable.
Scope
Before/after, event-study, and interrupted-time-series inference; "recorded nowhere" means neither own log nor retained platform change history.
What this licenses you to do
Log every advertiser-initiated change (timestamp, scope, intent) via a write-time hook covering humans and automations; refuse point attribution over any window whose change log is incomplete.