Preliminary control, also known as steering control or feed forward control, focuses on the resources that the organization brings in from the environment. It attempts to monitor the quality or quantity of these resources before they enter the organization.
Example: Preliminary Control could be technology, a process or people brought in to control or monitor a resource, i.e. a quality manager or department to ensure customer satisfaction by on time deliveries or accuracy in receipt of products ordered.
Screening Control
Screening control, also known as yes/no control or concurrent control focuses on meeting standards for product or service quality or quantity during the transformation process. Screening control relies on feedback processes. For example, when quality checks are used to provide feedback to workers manufacturing a product, the workers know what, if any, corrective actions to take.
Example: Screening control is just feedback on if the preliminary control is effective. So, in the example given for preliminary control, is bringing in a quality department accomplishing what we needed it to do (control accuracy).
Post action Control.
Post action control, also known as feedback control, focuses on the outputs of the organization after the transformation process is complete. Although post action control used alone may not be as effective as preliminary or screening control, it can provide management with information for future planning. Post action control also may be used as a basis for rewarding employees.
Example: Post Action Control, sticking with the original example for preliminary and screening control, could be rewarding the employees following protocol put in place from the quality department and meeting accuracy goals potentially set and agreed upon by the client and organization.