The five principles of lean include the following:

• Specify value desired by customers
  • Define value from the customers perspective and express value in terms of a specific product
• Identify the value stream
  • Map all of the steps…value added & non-value added…that bring a product of service to the customer
• Make the product flow continuously
  • The continuous movement of products, services and information from end to end through  the process
• Implement pull systems where continuous flow is possible
  • Nothing is done by the upstream process until the downstream customer signals the need
• Manage toward perfection
  • The complete elimination of waste so all activities create value for the customer