供应链管理Chapter5Risk Pooling and Forecasting.ppt

* Summary Demand planning/forecasting is the starting point of all planning The performance of forecasting approach can be evaluated based on various metrics  - MAD - MSE - MAPE Various forecasting approaches exist. Which one is appropriate depends on the situation. - Qualitative methods, - Causal models, or - Time-series models * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Other Factors of Forecasting * The Most Appropriate Technique Purpose of the forecast How will the forecast be used? Dynamics of system for which forecast will be made. How accurate is the past history in predicting the future? * Determine the Most Appropriate Technique * Evaluations of Two Forecasts * Bias in Forecast * Bias in Forecast * Reasons for Bias in Forecast Linear trend or non-linear trend Seasonality External factors, such as promotion and advertisement If relevant elements are not considered in the forecast, the forecast can become biased. These elements can include: * Qualitative Methods Qualitative Methods Sales Force Composite Panel of Experts Market Research Delphi Method Application Used to generate forecasts if historical data are not available (e.g., introduction of new product) Used to modify forecasts generated by other approaches (e.g., considering information not included in quantitative methods) * Sales Force Estimate Rationale Sales force is close to customer and has good information on future demands Approach Members of sales force periodically report their estimates. These estimates are then aggregated to generate the overall forecast Main advantages Sales force knows customer well Sales territories are typically divided by district/region. Sales forecasts can be broken down correspondingly * Sales Force Estimate Bias of sales force - Might have incentives to overestimate sales or underestimate sales - Might naturally be optimistic or pessimistic Sales force does not always have all informati