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Learn about demand and forecasting concepts, methods, and time series patterns for effective supply chain management. Discover key steps and actions for collaborative forecasting to reduce errors and improve decision-making. Understand when forecasting is inappropriate and how to adapt to uncertain demand situations. Gain insights on leveraging IT for data integration and process optimization in the forecasting process. Enhance your forecasting skills and optimize supply response strategies for better business outcomes.
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Demand and Forecast Dickson K.W. Chiu PhD, SMIEEE Text: Ballou - Business Logistics Management, 5/E (Chapter 8)
Learning Objectives • To understand some basic concept of demand and forecasting • To anticipate typical problems involved in demand and forecasting Dickson Chiu 2006
What’s Forecasted in the Supply Chain • Demand, sales or requirements • Purchase prices • Replenishment and delivery times Dickson Chiu 2006
Some Forecasting Method Choices • Historical projection • Moving average • Exponential smoothing • Causal or associative • Regression analysis • Qualitative • Surveys • Expert systems or rule-based • Collaborative Dickson Chiu 2006
Typical Time Series Patterns: Random Dickson Chiu 2006
250 200 Sales 150 100 Actual sales Average sales 50 0 0 5 10 15 20 25 Time Typical Time Series Patterns: Random with Trend Dickson Chiu 2006
Typical Time Series Patterns: Random with Trend and Seasonal Dickson Chiu 2006
Sales Time Typical Time Series Patterns: Lumpy Dickson Chiu 2006
Is Time Series Pattern Forecastable? • Whether a time series can be reasonably forecasted often depends on the time series’ degree of variability. Forecast a regular time series, but use other techniques for lumpy ones. How to tell the difference: • A time series is lumpy if where regular, otherwise. Dickson Chiu 2006
Analysis Details • See textbook if you are interested • Moving Average • Exponential Smoothing Formulas • Regression Analysis • Combined Model Forecasting • Note data requirements and timeliness requirement • Tracking signal monitors the fit of the model to detect when the model no longer accurately represents the data => events Dickson Chiu 2006
Actions When Forecasting is Inappropriate • Seek information directly from customers • Collaborate with other channel members • Apply forecasting methods with caution (may work where forecast accuracy is not critical) • Delay supply response until demand becomes clear • Shift demand to other periods for better supply response • Develop quick response and flexible supply systems, e.g., order-to-build of Dell Dickson Chiu 2006
Collaborative Forecasting • Demand is lumpy or highly uncertain • Involves multiple participants each with a unique perspective—“two heads are better than one” • Goal is to reduce forecast error • The forecasting process is inherently unstable Dickson Chiu 2006
Collaborative Forecasting Key Steps • Establish a process champion • Identify the needed information and collection processes • Establish methods for processing information from multiple sources and the weights assigned to multiple forecasts • Create methods for translating forecast into form needed by each party • Establish process for revising and updating forecast in real time • Create methods for appraising the forecast • Show that the benefits of collaborative forecasting are obvious and real Dickson Chiu 2006
Again much domain knowledge is required. Note the data / information requirements and how IT helps to collect / integrate the data for calculations and decision making. Capture forecasting signals (either determined by a business analyst or automatically by a sub-system) as events / exceptions / alerts and forward them to the appropriate system and personnel for decision / action. Collaborative forecasting as well as quick response and flexible supply systems requires much new IT in the process and information integration. Summary Dickson Chiu 2006