The short answer
Paid measurement raw data, reports and change receipts are handed over within the contract scope (free-snapshot raw data ages out after ninety days). The monthly close reads that month's observation, execution and conversion evidence side by side — and next month's priorities and the renewal scope are decided on that record, which you keep either way.
Why this matters
If the record leaves with the vendor, the next team has no before state. Everything measured up to that point stops working as a comparison.
Raw data, reports and change receipts are handed over within contract scope and sealed as they were, so a later round can be laid against them by whoever runs it.
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