Sign in

Glossary

Identifier map

A dated table of old identifier to new, applied on every upload before any measure, so a migration, a merge or a re-key joins history instead of breaking it. Old identifiers are never reused. Proposed pairs from pattern matching are confirmed by a person, never applied automatically.

DefinitionA dated table of old identifier to new, applied on every upload before any measure, so a migration, a merge or a re-key joins history instead of breaking it. Old identifiers are never reused. Proposed pairs from pattern matching are confirmed by a person, never applied automatically.

What drift does without it

Phantom churn, phantom new accounts, dormancy on half the book, concentration halved.

The threshold

New identifiers above a stated share of the base in one upload is a migration, and the run stops until the map exists.

How it is used

A dated table of old identifier to new, applied to every upload before any measure is computed, so that a system migration, a merger or a renumbering does not break history.

Example

After a system migration, account 40017 became C-88213 from 1 April. The map carries both, and the account's three-year history stays in one row.

Where it goes wrong

Handled by a one-off fix in a spreadsheet. The next upload brings the old identifiers back.