Workflow: Financial Model Validation

🌐 Languages: English

Estimated time: 30-45 minutes Difficulty: Intermediate Category: 📊 Administrative Professions: Finance managers, Controllers, Business owners

Use Case

You have a financial model (budget, forecast, pricing calculator) in Excel and need to:

Verify formula integrity across all sheets
Check for circular references or errors
Validate calculation logic
Document assumptions and dependencies
Create an audit trail for stakeholders

⚠️ Important: This workflow uses Cowork’s Excel generation capabilities (creating new analysis files). It does NOT use the Claude in Excel add-in (Microsoft Excel add-in for formula assistance). See comparison.

Prerequisites

Cowork enabled (Pro or Max subscription)
Financial model file (.xlsx) ready
Workspace folder created
Basic understanding of your model’s structure

Step-by-Step Instructions

Step 1: Prepare Model for Review

# Create workspace structure
mkdir -p ~/Cowork-Workspace/{input/financial-model,output}

# Copy your model to workspace
cp ~/path/to/your-model.xlsx ~/Cowork-Workspace/input/financial-model/

Tip: Make a backup of the original file before validation.

Step 2: Initial Structure Analysis

Request a high-level overview:

Analyze the Excel file at ~/Cowork-Workspace/input/financial-model/your-model.xlsx

Provide:
1. Sheet list with purpose of each
2. Key input cells (where assumptions are entered)
3. Key output cells (final results)
4. Dependencies between sheets

Save summary to: ~/Cowork-Workspace/output/model-structure.md

Step 3: Formula Audit

Check formula integrity:

Audit all formulas in ~/Cowork-Workspace/input/financial-model/your-model.xlsx

Create an Excel report at ~/Cowork-Workspace/output/formula-audit.xlsx with:

Sheet 1 - "Formula Inventory":
- Cell Reference
- Formula
- Sheet Name
- Formula Type (SUM, IF, VLOOKUP, etc.)
- References (which cells it depends on)

Sheet 2 - "Potential Issues":
- Cell Reference
- Issue Type (hardcoded value in formula, missing error handling, complex nested formula)
- Severity (Low/Medium/High)
- Recommendation

Sheet 3 - "Cross-Sheet Dependencies":
- Source Sheet
- Target Sheet
- Number of References
- Key Linked Cells

Step 4: Error Detection

Identify calculation errors:

Check ~/Cowork-Workspace/input/financial-model/your-model.xlsx for:

1. Cells with #REF!, #VALUE!, #DIV/0!, #N/A errors
2. Circular references
3. Hidden cells with formulas
4. Inconsistent formula patterns (e.g., row 5 uses different logic than rows 1-4)

Save findings to: ~/Cowork-Workspace/output/error-report.md

Step 5: Assumption Documentation

Extract and document assumptions:

Review ~/Cowork-Workspace/input/financial-model/your-model.xlsx

Create ~/Cowork-Workspace/output/assumptions.xlsx with:

Sheet 1 - "Input Assumptions":
- Parameter Name
- Current Value
- Unit
- Source/Justification
- Last Updated
- Sensitivity (Low/Medium/High impact on results)

Sheet 2 - "Calculated Assumptions":
- Parameter Name
- Formula
- Current Value
- Dependencies

Step 6: Sensitivity Check

Test assumption sensitivity:

For the financial model at ~/Cowork-Workspace/input/financial-model/your-model.xlsx:

Identify the 5 most critical input assumptions (those with highest impact on final results).

Create ~/Cowork-Workspace/output/sensitivity-analysis.md documenting:
- Which assumptions drive the most variance
- Recommended ranges for scenario planning
- Red flags if assumptions are changed

Step 7: Generate Validation Report

Compile findings into executive summary:

Create a Word document at ~/Cowork-Workspace/output/validation-report.docx

Include:
1. Executive Summary
   - Model purpose
   - Validation date
   - Overall health score (Pass/Warning/Fail)

2. Findings
   - Formula issues found
   - Errors detected
   - Assumption gaps

3. Recommendations
   - Critical fixes required
   - Best practice improvements
   - Documentation needs

4. Appendices
   - Detailed formula audit (reference to Excel file)
   - Assumption list (reference to Excel file)

Success Criteria

✅ Complete when:

All formulas documented and audited
No critical errors (#REF!, circular references) remain unaddressed
Assumptions are documented with sources
Validation report delivered to stakeholders

Common Pitfalls

Issue	Solution
Model too large (>10MB)	Split into modules, validate separately
Complex VBA macros	Cowork cannot execute macros—document manually
External data links	Note dependencies, validate data sources separately
Password-protected sheets	Unlock sheets before analysis

French Context Adaptations

For French TPE/PME:

Terminology:

Use French Excel function names: SOMME not SUM, SI not IF
Currency: EUR (€) instead of USD ($)
Date format: DD/MM/YYYY (European) not MM/DD/YYYY (US)

Compliance:

Document assumptions for expert-comptable review
Maintain audit trail for fiscal inspection (contrôle fiscal)
Reference French accounting standards (PCG - Plan Comptable Général)

Regional Settings:

When analyzing, use European Excel syntax:
- Formula separator: semicolon (;) not comma (,)
- Decimal separator: comma (,) not period (.)
- Example: =SOMME(A1;A2) not =SUM(A1,A2)

Advanced Tips

Large Models:

Process in batches: validate one sheet at a time
Focus on critical calculation paths first
Document module boundaries for clarity

Recurring Validation:

Save prompts for reuse each quarter/year
Create checklist for consistent validation
Track changes between validation cycles

Stakeholder Communication:

Generate executive summary first (1 page)
Provide detailed technical appendix separately
Use visual aids (charts) for assumption sensitivity

Example Prompt (Complete Workflow)

I have a financial model at ~/Cowork-Workspace/input/financial-model/budget-2026.xlsx

Execute this validation workflow:

1. Structure Analysis:
   - List all sheets with purposes
   - Identify input vs calculation vs output sheets
   - Save to structure-analysis.md

2. Formula Audit:
   - Inventory all formulas
   - Flag potential issues (hardcoded values, complex nesting)
   - Create formula-audit.xlsx

3. Error Detection:
   - Find #REF!, #VALUE!, #DIV/0! errors
   - Check for circular references
   - Report hidden formulas
   - Save to error-report.md

4. Assumption Documentation:
   - Extract all input assumptions
   - Document sources and sensitivity
   - Create assumptions.xlsx

5. Validation Report:
   - Executive summary (1 page)
   - Detailed findings
   - Recommendations
   - Save to validation-report.docx

Use European Excel syntax (semicolon separators, French function names).

Expense Tracking — Extract financial data from receipts
Workforce Planning — Validate headcount models
Budget vs Actual Analysis — Compare planned vs real expenses

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