The purpose of SPC is to build quality into the goods and services, rather than inspect poor quality out after completion. Components of the Control Process Carrying out the control process relies on the ideas of objectives, criteria, standards, and measures. We defined objectives in the Planning Units as desired outcomes. A criterion defines the specific scale we use to assess the desired outcome. A standard is the desired level of a criterion defined with respect to the objective.
Measures are the processes used to determine the actual level achieved on the desired criterion.
In conducting the control process, managers define criteria and standards which are congruent with the firm's operating objectives. We use measures to determine the actual level achieved on the specified criterion. Managers compare actual levels with the defined standards. If managers observe discrepancies, they must take action to bring the actual performance of the firm into compliance with the objectives. This often takes the form of revising operating procedures so the actual results are congruent with standards.