ERP Modernization · November 5, 2026 · 6 min read
A matching total isn't enough: checking municipal ERP conversion data
Before accepting an ERP conversion, have Finance and department staff check missing records, duplicate invoices, account mappings and open items, then repeat the checks after corrections.
By Altioras Civic
Key takeaways
- Compare converted balances by fund and account, and account for every in-scope source record, including rejects and approved exclusions.
- Have staff check converted invoices, purchase orders and other open items through the tasks they will perform after go-live.
- Keep the extract, mapping version, import results and reconciliations together so reviewers can tell which conversion run they accepted.
Give Finance more than a balanced trial balance
A conversion can produce the right grand total while putting balances in the wrong fund or leaving staff with duplicate open invoices. Before accepting a rehearsal, have Finance compare the balances and the records behind them. Department staff should then check that those records support the work they need to do.
For a Munis/EERP project, record the exact source and target products, releases and modules in the conversion plan. Tyler describes Enterprise ERP as powered by Munis. Confirm the available exports, import results and report names with your implementation team; this checklist does not assume a particular screen, license or conversion utility.
GAO's data reliability guidance considers accuracy, completeness and whether data is suitable for its intended use. The working checks below apply those principles to a municipal ERP conversion rehearsal. Adapt them to the approved conversion scope and your municipality's accounting procedures.
Sources: Tyler Technologies — Enterprise ERP, powered by Munis; U.S. GAO — Assessing Data Reliability (GAO-20-283G, December 2019)
Keep one conversion run together
Give each rehearsal a run ID. Save the source extract, extraction time, fiscal cutoff, record selections, approved mapping version and target environment. Retain the load results and the reports staff use to reconcile that run. If the source system stays open, identify transactions entered after the extract so reviewers can distinguish later activity from a conversion omission.
Have each department approve what will move: master records, opening balances, open transactions and any selected history. Record what will remain in the old system or an archive, who can retrieve it and how staff will answer a historical inquiry. A record intentionally retained elsewhere needs an approved disposition; it should not disappear into an unexplained count difference.
Define how source identifiers will link to target identifiers. Preserve leading zeros, document numbers and line numbers where they are significant. If accounts are combined or split, retain the mapping that explains the relationship. Equal raw row counts are not an appropriate target when the approved design deliberately changes the record structure.
Check and accept one conversion run
- Step 1Identify the runSave the source cutoff, mapping version and target environment.
- Step 2Account for recordsTrace in-scope records through loaded, rejected and excluded results.
- Step 3Test the detailReconcile balances by fund and account; test converted open items.
- Step 4Review the resultDepartment owners review results; sponsor decides whether to proceed.
Check records, mappings and balances separately
Start with the full set of in-scope source identifiers. Use approved queries or comparison tools to identify missing records, unexpected target records and duplicate identifiers. Keep rejected records and approved exclusions visible. Define the key at the right level: an invoice number alone may not identify a vendor's invoice line uniquely.
Then reconcile amounts at the level Finance will use them. Compare fund and account, followed by department, project or grant where those dimensions are in scope. Review debits and credits separately where appropriate. Check opening balances and period activity consistently, and confirm the conversion design prevents open-item loads from duplicating amounts already established in the ledger.
Hypothetical example: one fund is overstated and another is understated by the same amount. The overall total agrees. A comparison by fund exposes the error; tracing the affected source accounts through the approved mapping tells the team where to investigate. Likewise, a missing invoice and a duplicated invoice of the same value can leave both the count and total unchanged. Comparing their identifiers reveals the problem.
Use this table during the rehearsal review. Add the actual report filenames, source and target IDs, differences, assigned employee and due date to the team's internal copy.
| What to check | Records or results to compare | Who reviews it |
|---|---|---|
| Scope and cutoff | Compare extract selections and dates with the approved conversion scope. Identify excluded history and transactions entered after the extract. | Department data owner and conversion lead |
| Missing and duplicate records | Compare in-scope source keys with loaded target records, rejects and approved exclusions. Investigate unexpected target records and repeated keys. | Data analyst and department reviewer |
| Account mappings | Trace source fund, account and other required dimensions to approved target combinations. Check every portion of an approved split or combination. | Finance account owner |
| Balances | Compare source and target trial balances by fund and account at the same cutoff. Reconcile subledger totals to their ledger control accounts as designed. | Finance reconciliation preparer and reviewer |
| Open transactions | Compare unpaid invoices, credits and remaining purchase-order amounts, including vendor, status and original reference. Check the next permitted task in a test environment. | AP or Purchasing lead |
| Master data and links | Check selected vendor, customer or employee records, active status and links to transactions. Compare sensitive fields only in approved restricted storage. | Relevant department owner |
| Correction and acceptance | Repeat the affected comparisons after an approved fix. Link the new run, remaining exceptions, test results and department decision. | Conversion lead and authorized department approver |
Use converted records in the test environment
Have AP find a converted unpaid invoice, inspect its vendor and due date, and confirm that its remaining balance and payment status are correct. Have Purchasing follow a converted open purchase order through the next agreed test step. Include credits, partially completed items and inactive records where they affect the approved scope.
Keep these exercises in the authorized test environment. Staff should compare the result with the approved conversion and process design. An import marked successful does not establish that a transaction has the correct status, relationships or accounting treatment.
For each exception, record whether the correction belongs in the source, the mapping, the load procedure or the report. Obtain the normal approval, repeat the conversion as planned and rerun the affected checks. Avoid unexplained balancing entries or manual edits that make one report agree while leaving the conversion error unresolved.
Have AI look for missing conversion tests
A separately approved AI tool could compare redacted mapping descriptions with the team's test list. Ask it to identify rules that have no test and return the rule ID, a proposed scenario and the source reference. For example, it could suggest checking an account split when the existing tests cover only one-to-one mappings.
Have the Finance or department data owner check each suggestion against the approved mapping before adding it to the test plan. Staff define the expected results and decide whether the added test is useful. Use deterministic queries and approved calculations for counts, amounts and control totals. This proposed use of an external tool leaves record changes, account mappings and acceptance with the authorized staff.
Record what the department accepted before deciding on cutover
Have each department approver identify the run reviewed, completed checks, remaining exceptions and effect on daily work. GFOA recommends documenting financial procedures and distinguishing responsibility from transaction authority. Keep the conversion decision within those existing approval arrangements.
Rehearsal acceptance does not cover a later final load automatically. Repeat the agreed checks for the final extract and target load, including transactions since the previous rehearsal. Give the sponsor the unresolved items and their operational consequences before the cutover decision.
Bring the next working session one conversion run and its source-to-target comparisons. Altioras Civic's ERP Implementation & Remediation service can help Finance, departments and the implementation team work through the differences and retest corrections.