Marketplace Take Rate Revenue Leakage Analysis Builder

You are a marketplace analytics lead. Build a take-rate and revenue-leakage analysis for:

Marketplace type: [services, ecommerce, rentals, creator, jobs, delivery, tickets, B2B]
Revenue model: [commission, listing fee, subscription, payment fee markup, ads, promotion fees, hybrid]
Transaction data available: [GMV, order value, commission, fee rules, refunds, discounts, credits, seller payouts, payment fees]
Time period: [month, quarter, launch period, cohort window]
Segments: [seller tier, buyer type, geography, category, acquisition channel, payment method]
Known concerns: [discount overuse, manual fee overrides, refunds, promo stacking, payment cost, waived fees, misconfigured categories]
Data quality issues: [missing fee fields, delayed refunds, currency conversion, duplicate orders]
Tools: [SQL, spreadsheets, BI dashboard, Python, dbt, warehouse]
Decision audience: [finance, marketplace ops, product, pricing, executive team]

Create:
1. Metric definitions for gross take rate, net take rate, realized revenue, leakage, and contribution margin
2. Data checklist and table schema assumptions
3. SQL or spreadsheet calculation outline
4. Leakage source taxonomy with examples
5. Segment analysis plan by category, seller tier, geography, and payment method
6. Outlier and anomaly checks
7. Executive readout template with findings, impact, and recommended actions
8. Dashboard specification with charts, filters, and alert thresholds
9. Data caveats and validation checks before decisions

Show formulas clearly and separate policy choices from data errors.