A spreadsheet may appear to contain data and formulas.
A financial spreadsheet often contains much more: a definition of which source is authoritative, a hierarchy for resolving conflicts, rules governing approval, conditions that allow an item to advance, and assumptions about how the workbook may change.
These rules form an unwritten constitution.
Before translating a spreadsheet into code, identify the constitution already hiding inside it.
Article 1: Authority
Which system or document is permitted to define each fact? The authoritative source for a legal entity name may differ from the source for an invoice amount, payment status, contract period, or approval state.
Article 2: Precedence
When two valid-looking sources disagree, which one wins? A hierarchy might place an approved contract above a system of record, followed by an operational tracker and then a historical fallback. The hierarchy varies by field, but it must be explicit.
Article 3: Permission
Who may change, approve, or override a value? Editing access is not the same as decision authority. A person may be able to modify a cell without being authorized to approve the resulting action.
Article 4: Transition
Which event permits an item to move from one state to another?
| State | Required evidence | Authorized transition |
|---|---|---|
| Pending | Source document and owner | Submit for review |
| Under review | Policy and supporting context | Approve or create exception |
| Approved | Reviewer and timestamp | Prepare controlled action |
| Executed | Destination record and unique event | Begin reconciliation |
| Reconciled | Comparison and variance result | Close the item |
A descriptive edit should not accidentally trigger the same event as an authorized status change.
Article 5: Exception
Which conditions prevent the normal workflow from continuing? Missing evidence, duplicate identifiers, conflicting sources, invalid benchmarks, material variances, and unauthorized approvals need distinct treatment.
Article 6: Evidence
A final number is not enough. The record may also need source identifiers, input values, the applied rule, exception status, reviewer, timestamp, approval, destination, and reconciliation result.
Article 7: Amendment
How are rules changed? A workbook can be altered without leaving a meaningful explanation. A governed workflow needs versioning, testing, approval, and a record of when new logic took effect.
When the constitution remains implicit
If these rules exist only in one accountant’s memory, the organization becomes dependent on that person. If they are scattered across formulas, comments, emails, and chat messages, automation can reproduce inconsistencies rather than eliminate them.
If the source hierarchy is unclear, the system may produce a technically correct calculation based on the wrong fact.
A practical worksheet
| Question | Example |
|---|---|
| What does this field mean? | Approved payment amount |
| What is authoritative? | Approved finance tracker |
| What is the fallback? | Executed contract |
| When is fallback permitted? | Primary source is missing, not contradictory |
| Who may approve a change? | Designated finance approver |
| Which values are invalid? | Blank, negative, or nonnumeric amount |
| What happens on conflict? | Stop and create a review item |
| What evidence is retained? | Source, old value, new value, approver, timestamp |
This exercise is useful whether the implementation remains in Excel, moves to Python, or becomes part of a finance platform.
The leadership decision
Leaders should not begin by asking which automation tool to buy. They should first ask which rules, authorities, exceptions, and evidence the current process depends on.
Tools execute the operating model they are given. If the operating model remains implicit, the tool will not make it clearer by itself.
Source notes
- DFIN, Financial Close: Speed, Accuracy and Control. Discusses documented processes, approval hierarchies, segregation of duties, spreadsheets, and version control.
- Nomentia, Spreadsheet-Supported Treasury Control. Distinguishes spreadsheet flexibility from the ownership, permission, versioning, approval, and audit layers required for controlled processes.