Map meaning before numbers
List each source code with its description, scope boundary, unit, and destination code. Mark one-to-many and many-to-one relationships. Do not map by similar code numbers alone.
Two systems may use the same label for different scope. Start with the cost code mapping guide and document package-specific exceptions beside the standard company structure.
Test the crosswalk with estimate data
Run quantities and costs through the mapping, then reconcile source and destination totals. Review unmapped codes, duplicate allocation, rounding, allowances, indirect costs, and contingency. Sample records in both directions so a reviewer can trace a report line back to the source estimate.
AACE recommended practices on cost estimating provide general reference material. The crosswalk itself must reflect the contractor systems and approved project coding.
| Check | Evidence |
|---|---|
| Meaning | Scope and unit definition |
| Mapping | Source-to-destination relationship |
| Balance | Reconciled quantities and costs |
| Change | Owner, date, and affected revisions |
Control changes after handoff
Assign an owner for code additions and mapping changes. Record effective dates and the estimate or reporting revisions affected. A changed mapping can move reported cost without any change to the underlying estimate, so explain those transfers separately.
Reconcile the approved mapping during the schedule of values handoff. Preserve the crosswalk version with every report or export that depends on it.
