Practical software assurance playbook
Spreadsheet Assurance Playbook
A proportionate method for deciding when a spreadsheet matters and how to control formulas, data, use, change, and retirement.
Professional interpretationEducational practitioner method · Quality review required for case-specific use
Decision and evidence workflow
Work through the assurance boundary
- 01
Intended Use
- Decision
- State the calculation, record, report, or decision the spreadsheet supports and who relies on the output.
- Evidence
- Approved intended use, owner, version, and use boundary.
- 02
Complexity
- Decision
- Inventory formulas, lookup tables, macros, external links, hidden content, protection, and manual steps.
- Evidence
- Complexity inventory with critical cells and dependencies.
- 03
Data Inputs
- Decision
- Identify source, units, ranges, completeness, transcription, import, and stale-data risks.
- Evidence
- Input specification and source-to-cell traceability.
- 04
Calculation Risk
- Decision
- Trace formula, reference, rounding, unit, copy/paste, and sequence failures to the decision they can affect.
- Evidence
- Function-level risk assessment and critical acceptance criteria.
- 05
Protection
- Decision
- Control approved templates, formulas, critical cells, access, storage, versioning, and unauthorized change.
- Evidence
- Protection configuration and controlled-copy procedure.
- 06
Verification
- Decision
- Use independent calculations, boundary values, known-answer sets, negative tests, and realistic workflow checks.
- Evidence
- Executed evidence with inputs, expected results, actual results, and exceptions.
- 07
Change Control
- Decision
- Assess formula, structure, reference-data, platform, protection, and intended-use changes before release.
- Evidence
- Version history, impact assessment, regression decision, and approval.
- 08
Periodic Review / Retirement
- Decision
- Review access, use, incidents, copies, dependencies, platform compatibility, retention, and replacement.
- Evidence
- Periodic review or retirement record with migration and archival checks.
Release gate
Before the decision is defended
- The approved file and authoritative location are unambiguous.
- Critical formulas and data transformations are independently challenged.
- Protection and change controls match the actual use environment.
- Users can identify the current version and recover required records.
Scope and limitations
What this playbook does not establish
- Cell protection is not evidence that calculations are correct.
- A macro-free workbook can still be high risk when it drives a regulated decision.
- Complex shared spreadsheets may be better replaced by a controlled application.
Use applicable regulations, final guidance, organizational procedures, and subject-matter review for the actual system and jurisdiction.