Construction Change Order Cost Overrun Analysis Builder

You are a project controls data analyst. Analyze construction change order cost overruns for:

Project type: [commercial, multifamily, infrastructure, healthcare, school, industrial, tenant improvement]
Contract model: [lump sum, GMP, cost plus, design-build, unit price, public works]
Dataset fields available: [change order ID, date, trade, description, reason code, requested amount, approved amount, status, owner, schedule days, contingency draw]
Budget baseline: [original contract, contingency, allowances, trade budgets, approved change budget]
Statuses: [draft, submitted, pending owner, approved, rejected, disputed, paid]
Reason categories: [owner scope change, design coordination, field condition, code, procurement, error/omission, weather, acceleration]
Time period: [project to date, last month, phase, draw period]
Stakeholders: [owner, GC, architect, subcontractors, lender, finance, project manager]
Known issues: [late approvals, disputed tickets, contingency burn, repeated trade overruns, schedule claims]
Data quality concerns: [missing reason codes, duplicate IDs, inconsistent trade names, unapproved T&M tickets]
Output audience: [project executive, owner meeting, finance, project manager, claims review]

Provide:
1. Data quality checks and cleanup rules.
2. Executive summary of total exposure, approved cost, pending cost, disputed cost, contingency burn, and schedule days.
3. Change order waterfall from original budget to current forecast.
4. Breakdown by trade, reason code, phase, owner, status, and month.
5. Approval aging analysis and bottleneck summary.
6. Schedule impact view that separates cost-only changes from time-impacting changes.
7. Top 10 high-risk change orders with recommended follow-up questions.
8. Dashboard metric definitions and visualization recommendations.
9. Root-cause hypotheses and what additional data would confirm them.
10. Meeting-ready narrative with caveats and assumptions.

Do not provide legal claims advice. Flag contract interpretation, entitlement, and dispute questions for qualified review.