Associates in Process Improvement (API 
) have elaborated on J. Edwards Deming’s 1951 sketch of Business as a System.
Deming's 1951 diagram for Japanese engineers. Business as a System.
API's model includes three distinct levels referd to as the Driver Level, the Mainstay Level, and the Support Level. They also add Purpose, Metrics, Customers and Suppliers to the process oriented levels.
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Stafford Beer’s Viable System Model, might locate the Support Level in Systems 2, 3* and 3. The Mainstay Level includes all the units that produce goods and services used by direct external customers. The Driver Level would be represented in Beer’s System 3, 4, and 5.
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Sofi has 12 functions or domains of responsibility 66 process link types in which to locate all the processes in any enterprise.