Post on 25-May-2015
description
Demand Forecasting
Vincent 10/8/2010
Stock vs. Non-stock
• Ranking products based percentage of total activity (number of hits)
• Non stock items– Low activity and high value items
• Stock items– High activity and low value items
Demand Forecasts and Usage
• Products with sporadic usage– Maintain the stock based on multiple of the
typical sales or usage quantity. – Roll up the usage to the central warehouse – Or set up as non-stock items?
• Products with recurring usage
Forecast for items with recurring usage
• Past usage• Internal trends• External trends– Weather, economy
• Collaborative forecasts– Sales input– Special promotion
• Forecast horizon
Past usage
• Direct or drop shipments– Direct shipments should not be included.
• Shipping an order from an alternate warehouse instead of the designated one– Usage should be recorded with the designated one.
• Usage and substitute products• Record usage when a customer wanted the product
– Required date vs. actual ship date?• Usage and transfers
– Treating other warehouses as customers?
Utilizing Usage to Forecast Demand
• Seasonal products– Consider usage from the last year– Adjusting usage for unusual usage– Weighed average • 3x same month LY +2x next month + 1 following month
– Use seasonal index– Applying trend factors • compare last year’s usage with this year’s usage
Determining the Best Forecast Formula
• Forecast error % = absolute value of (forecast –usage)/actual usage
Questions?