Where each record came from, and when.
Nothing is assembled before the target is described in writing. Each stage writes down what it changed and why. The result is auditable line by line.
Jurisdiction split
Separating records by the rules that apply where the person is, not where the file was built.
Consent position
Stating what basis exists for contacting each segment, and where that basis is absent.
Re-check scheduling
Deciding how often each part of a file needs looking at again, by how fast it goes out of date.
We are happy to say a job is not worth doing, and we do say so.