Kaizen is a Japanese philosophy of continual improvement. It means "change for good" and involves making small, incremental changes to processes to improve efficiency and quality. A kaizen activity aims to permanently improve the value stream by moving from the current state to a defined future state. For a change to qualify as true kaizen, it must positively impact the overall metrics of the value stream such as lead time, quality, and productivity. Local improvements may not qualify as kaizen if they do not benefit the entire value stream.