On this site, record hygiene covers two problems in an owner list: the same owner stored more than once, and contact data that has stopped reaching the owner. Both are measured from a sample of the list before anything is cleaned, and both are fixed record by record, with the original values kept beside the new ones.
The reading order
A list that has never been checked starts with the record source inventory. Its tables trace each field to the source that supplied it and the date it was last confirmed, and its twelve checks put the fixes in order.
How to find duplicate records without losing their history comes next. It measures a list's duplicate rate from a random sample, then runs three matching passes and a merge that can be undone. Its real case is the Census Bureau's mailing lists for the 1987 and 1992 Censuses of Agriculture.
How fast owner records go stale follows. It sorts phones and addresses by the time since each was last confirmed, samples each age group, and sets a re-check age from the share that fails. Its real case is a Postal Service inspector general report on mail that could not be delivered to the address on it.
Why duplicates come before decay
A decay sample drawn from a list that still holds duplicates can count one owner twice, and a phone confirmed on one copy stays unconfirmed on the other. After the merge, each age group holds each owner once, and the confirmation dates from every copy sit on one record.
What these guides leave out
Buying contact data, and comparing providers by what reached an owner, belong to the enrichment guides. Deciding who belongs on a list, and what to say when an owner answers, is outside the subject of this site.
Reading path
- How to find duplicate records without losing their history
How matching passes and a person's review find duplicate owners, and how a merge keeps every original record so it can be undone.
- How fast owner records go stale
How a dated sample from each age group measures how fast one owner list's phones and addresses stop reaching owners.
Worksheets for this guide
- The record source inventory
A printable worksheet that traces each field in an owner list back to its source and to the date it was last confirmed.