Phase 04 of 08
Data migration
Typically 5-15% of total project cost. Extracting, cleansing, transforming, and loading data from legacy systems. Range is wide because the dirtier the source data, the more this phase costs.
What's included
- ETL development for each legacy source
- Data-cleansing rules and tooling
- Trial migrations (typically 3-5 rounds before go-live)
- Reconciliation reporting
- Cutover plan and rehearsal
- Archival of legacy systems
Common overruns
- Discovery that legacy data quality is far worse than assumed
- Multiple legacy ERPs that disagree on the same record
- Trial migration cycles that surface new validation rules each time
Basis
Digital Signet allocation model. The band widens sharply the dirtier the legacy source data is.
Reviewed 2026-09-04
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