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MODEL ASSUMPTIONS & PARAMETERS
All blue values are user-adjustable inputs
General Parameters Shortage / Stockout Cost Parameters
Parameter Value Unit Description Parameter Value Unit Description
Working Days per Year 252 days Business days excluding holidays Lost Sales Cost (per unit) $50 $ / unit Revenue lost per stockout unit
Planning Horizon 12 months Forward planning period Backorder Cost (per unit) $15 $ / unit Cost to expedite backordered items
Review Period 30 days Days between inventory reviews Customer Goodwill Cost $25 $ / incident Estimated loss of customer loyalty
Warehouse Capacity (units) 50,000 units Maximum storage capacity Emergency Shipment Premium 0.5x multiplier Premium over standard freight
Currency USD   Reporting currency Target Fill Rate 97.0% % Desired order fill rate
Inflation Rate (Annual) 3.0% % Expected annual cost escalation
Tax Rate 21.0% % Corporate tax rate for cost calculations ABC Classification Thresholds
Discount Rate (WACC) 8.0% % Weighted average cost of capital Class Cumulative % Typical SKU % Description
A - Critical 80% 10-20% High value, tight control, frequent review
Holding / Carrying Cost Components B - Important 95% 20-30% Moderate value, moderate control
Cost Component Rate (%) Unit Description C - Standard 100% 50-70% Low value, simple controls, bulk ordering
Cost of Capital 8.0% % of value Opportunity cost of invested capital
Storage Cost 4.0% % of value Warehousing, rent, utilities Service Level & Safety Stock Parameters
Insurance 1.5% % of value Inventory insurance premiums ABC Class Service Level Z-Score Review Frequency
Obsolescence / Shrinkage 3.0% % of value Loss from damage, theft, expiration A - Critical 99.0% 2.33 Weekly
Handling & Labor 2.0% % of value Material handling labor costs B - Important 95.0% 1.65 Bi-weekly
Taxes (Property) 1.0% % of value Property taxes on inventory C - Standard 90.0% 1.28 Monthly
Total Holding Cost Rate 19.5% % of value Sum of all carrying cost components
Lead Time Assumptions
Ordering Cost Components Parameter Value Unit Description
Cost Component Value Unit Description Default Lead Time (Domestic) 7 days Standard domestic supplier lead time
Purchase Order Processing $25 $ / order Admin cost per PO Default Lead Time (International) 30 days Standard international lead time
Receiving & Inspection $15 $ / order Inbound quality check cost Lead Time Variability (Std Dev) 3 days Standard deviation of lead time
Transportation / Freight $35 $ / order Average shipping cost per order Demand Variability (Std Dev %) 15.0% % of avg Coefficient of variation for demand
Communication & Follow-up $5 $ / order Supplier communication
System / IT Processing $10 $ / order ERP transaction cost
Total Ordering Cost per Order $90 $ / order Sum of all ordering costs
Notes:
1. All blue-colored values are user inputs that can be modified to calibrate the model.
2. Holding cost rate is used in EOQ and carrying cost calculations across all items.
3. Service levels and Z-scores drive safety stock calculations by ABC class.
4. Lead time assumptions serve as defaults; item-level overrides are set in Inventory Data.
5. Sample data provided for demonstration. Replace with actual operational data.