Forecasting high-detail

Forecasts are developed at a level of detail that is not actionable — This is a complementary point to the first one. That means the information is at too high a level, too broad in scope, or just plain not directly related to what must go into a master schedule. The result is a high-level forecast that gets modified so much it becomes meaningless for the needs of factory planning. 

Most forecasting is done at a high level of detail that focuses on a product category or family, a market or region, and a period of weeks or months. Accuracy and efficiency in supply chain fulfillment require a much lower level of detail, tracked online and kept in synchronization with actual customer withdrawals. 

As we get closer to real demand then clearly the plan has become much more detailed. Ideally nothing is finally assembled, configured or packaged until we know what the customer s order specifies, To achieve this ideal state clearly requires a high level of agility - a challenge that will be addressed in Chapter 5. Even if the customer s required delivery lead time is less than the time we need to make/source and deliver and we have to make inventory ahead of time, at least the forecast will be more accurate since the forecast horizon is closer. 

These failures are those caused by common modes or events, or which have a cascading effect. High levels of safety needed from essential systems are usually achieved by some form of fail-safe design as detailed in Chapter 7. However, in spite of these precautions, there are various threats to the independence of the chaimels of redundant systems which may lead to multiple failures at higher rates than would be forecast by calculating the multiple rates from the failure rates of the component channels alone (Lloyd and Tye, 1995). 

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