Four Ms

Synonym(s):  4M

The variables that a production system manipulates to produce value for customers. The first three are resources, the fourth is the way the resources are used.

In a lean system, the Four Ms mean:

  1. Material—no defects or shortages.
  2. Machine—no breakdowns, defects, or unplanned stoppages.
  3. Man—good work habits, necessary skills, punctuality, and no unscheduled absenteeism.
  4. Method—standardized processes, maintenance, and management.
From the Lean Lexicon 5th Edition
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