Lean is largely about satisfying customer requirements. That’s nearly impossible if the lean practitioner doesn’t understand demand. In fact, misunderstand average daily demand, and the impact can be significant, including inaccurate takt times, improper demand segmentation, poorly sized kanban, and incorrect reorder points. Calculating average daily demand can be deceptively complex. Here are a handful of things to consider.

SKU and part number vs. product family. Kanban is applied at the SKU (stock-keeping unit) and part number level, so average daily demand must be calculated at that level as well. When calculating takt time, average daily demand is often, but not always, determined at the product family level, or at least the group of products or services that are produced or delivered within a given line, cell, or team.

True demand. Do not blindly accept what was sold, produced, processed, purchased, or issued as true historical demand.

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