Elaborating actual lead time with both management and execution data

Many lean management initiatives are achieved worldwide. Most often the focus of these projects is to reduce lead time in order to improve enterprise responsiveness and financial health. Usually, lead time is estimated by drawing up a value stream map and by estimating inventories and flow times all along it. This current practice is not accurate, exhaustive and relevant enough to us when managing a real ongoing improvement project. We suggest in this paper a new way of elaborating lead time for each product, taking into account all its components and using genealogy and purchasing costs data.