Muda of inventory occurs when materials or inputs stack up before a step in the process; this phenomenon is also called a bottleneck.
Inventory waste can occur when items are purchased or created before they are needed in a process. Inventory can also occur in work queues, digital data queues, or even email inboxes. If you receive 300 emails a day and you are only handling 30
of them on a regular basis, you have a process problem with your communications.
While inventory waste can occur in any process, it is especially common in processes that operate in batches. Traditional lean wisdom says to avoid batch process – processes that involve creating a certain number of products or outputs before pushing them down the line. Reducing batch size lowers lead times-the time it takes to deliver the end product. It also reduces the amount of inventory that occurs before each step of the process.
You can reduce waste of inventory by understanding a process and basing inventory decisions on historic metrics.