Why spreadsheets matter before ERP migration
In many organisations, spreadsheets operate as informal business systems. They calculate prices, forecast demand, allocate resources, reconcile transactions, track projects, manage exceptions and generate management reports.
These workbooks may not appear in the formal application architecture, yet the migration can fail if their logic is not captured. A new ERP platform may reproduce the visible workflow while missing the formulas, assumptions and dependencies that employees rely on every day.
It is: “What business decisions, calculations, outputs and controls depend on this workbook, and what must be preserved or redesigned?”
Common spreadsheet risks during migration
What should be analysed before migration
1. Workbook structure
Start by identifying the workbook's sheets, tables, named ranges, formulas, links and output areas. This establishes whether the workbook is a simple data-entry tool or a deeply interconnected operational system.
2. Business purpose
Determine what process the workbook supports and how people use its outputs. Automated analysis can identify likely purpose, but business-owner validation is still essential where labels, assumptions or manual steps are unclear.
3. Key outputs
Identify the outputs that influence decisions, reports, approvals, payments or customer activity. These outputs should become part of migration requirements and later form the basis of acceptance testing.
4. Formula and dependency relationships
A formula inventory is useful, but dependency relationships are more valuable. They show how inputs flow through calculations and which downstream outputs may be affected by a change.
5. Cross-sheet references
Heavy cross-sheet referencing is a sign that the workbook may be difficult to separate into independent requirements. These relationships should be understood before designing ERP data models, workflows or reporting logic.
6. Workbook-version differences
When several versions exist, compare them systematically. Look for added, removed or changed formulas, fields, sheets, structures and output logic. Otherwise, the migration team may document the wrong version.
7. Complexity and review indicators
Complexity indicators help prioritise discovery effort. A workbook with thousands of formulas and extensive cross-sheet dependencies should not be treated like a simple template, even if both are stored as Excel files.
How workbook analysis improves ERP requirements
Workbook findings should be translated into requirements that business analysts, solution architects, developers and testers can understand. The objective is not to recreate every spreadsheet cell inside the ERP platform. It is to preserve the necessary business outcomes and redesign the process deliberately.
Useful requirement categories include:
- Required inputs and data sources.
- Calculation and transformation rules.
- Approval, exception and manual-intervention points.
- Required management and operational outputs.
- Data-quality and validation controls.
- Frequency, timing and ownership of the process.
- Historical comparison or audit requirements.
Use the workbook findings to design UAT
Workbook analysis can strengthen user acceptance testing by identifying representative calculations and key outputs that must be validated in the new platform.
Instead of asking users to test the entire ERP implementation without a clear baseline, the team can build focused scenarios around known workbook outputs, changed formulas, exception cases and downstream calculations.
For each important workbook output, identify the inputs, calculation path, expected result and business owner responsible for approval.
Manual discovery versus structured workbook analysis
Manual workbook review remains valuable, especially where process context and business interpretation are required. The challenge is that manually tracing thousands of formulas and references can be slow, inconsistent and difficult to repeat.
A structured assessment helps create an evidence base before workshops begin. Business analysts can then spend more time resolving genuine questions instead of using interviews to reconstruct basic workbook structure.
Recommended migration-discovery deliverables
- An executive workbook overview.
- A list of sheets, tables, formulas and cross-sheet relationships.
- A documented statement of business purpose.
- An inventory of key outputs.
- A formula and dependency summary.
- A workbook-version comparison where multiple versions exist.
- A list of changed outputs and affected downstream calculations.
- Complexity and risk indicators.
- Questions requiring business-owner confirmation.
- Recommendations for requirements, testing and migration planning.
When should an organisation commission a workbook assessment?
A structured assessment is especially useful when:
- The workbook is business-critical or frequently used.
- Only a small number of employees understand it.
- The workbook contains many formulas or connected sheets.
- Several versions circulate across the organisation.
- The process is being moved into ERP, CRM or custom software.
- The workbook supports finance, operations, supply chain or management reporting.
- The organisation needs better governance, handover or audit evidence.
Conclusion
ERP migration should not begin with the assumption that a spreadsheet is merely a temporary data source. In many cases, it is the current implementation of the business process.
Understanding workbook purpose, formulas, dependencies, outputs and version changes gives the migration team a stronger foundation for requirements, solution design, testing and business approval.
IC-Flow is designed to support this discovery by turning complex workbooks into structured, decision-ready intelligence before migration, automation or operational change.