The Language of Lean
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Common Terminology

Lean Terminology


Process that corresponds to where master production scheduling is done

Pacemaker process

In Lean Production, the pacemaker is the point in the overall process that is scheduled. 

Load leveling (Leveled MPS)


The foundation of the Toyota Production System (including Just-in-Time) is leveled production or Heijunka.

Finishing schedule

Heijunka or Leveling box contents

A Heijunka box is a visual scheduling mechanism that distributes the finishing schedule into small time increments.

Mixed model master schedule

Level mix (schedule at the pacemaker)

Heijunka includes both leveling volume AND leveling mix. 

Safety stock (to buffer demand variability)

Buffer stock


Safety stock (to buffer supply variability)

Safety stock


Predetermined standard inventory buffer



Mixed model frequency (for master scheduled items), frequency that a process can produce all high volume items

EPE Interval or EPE I

The EPE Interval determines how often each item can be produced without exceeding available capacity and with the smallest possible lot size.  The calculations of takt time and the EPE Interval are the most important calculations involved in setting up a lean execution system. 

Process family

Product family

In Lean, a product family corresponds to all the different products that go through the same pacemaker and which share the same value-stream. 

Process (more precisely: the network or processes and operations through which material and information flow as a product is produced)



Supply chain

Extended value-stream


Process mapping

Value-stream mapping


Supply chain mapping

Extended value-stream


Rate of customer demand

Takt time

Understanding the takt time allows a company to synchronize production with the customer demand. 

Amount of time required to produce one container of a product in the pacemaker process

Pitch or takt image

Sometimes described as the management time frame, pitch is used for two important activities: 


  • Establishing the increment of work to be delivered to and taken away from the pacemaker process.
  • Measuring pacemaker performance. 

Continuous improvement


Kaizen is the term to describe continuous improvement, Kaizen blitz is the term commonly used to describe a focused and intense, short-term improvement activity




Strategic planning

Hoshin kanri