The deeper we understand the nature of organizations as systems, and focus upon their purpose, the more profoundly we develop customer-in thinking. This should lead us to view the SIPOC model of a business as a pull system rather than a push system. That is, the purpose of a business organization as a system is to serve its customers; it succeeds and makes a profit to the extent that it serves well its customers; everything begins with the customer who pulls into the organization the suppliers' inputs, which are processed into outputs, that meet the needs of customers