Describe the various elements of a control system.

Any control system has four elements:
1) A standard or goal: Goals and standards are defined during planning and design processes. They establish what is supposed to be accomplished. These goals and standards are reflected by measurable quality characteristics, such as product dimensions, service times, or employee behavior.
2) A means of measuring accomplishment: Measuring quality characteristics may be accomplished through some sort of inspection activity.
3) Comparison of results with the standard to provide feedback: By comparing results with the standards or goals, one can determine whether corrective action is needed. Many companies use statistical process control as a means of signaling when deviations from standards require corrective action.
4) The ability to make corrections as appropriate: Corrective action might entail adjusting machine settings or retraining employees to provide effective service.