Good instructors constantly act on the results of assessment. When students don't seem to be achieving desired outcomes, instructors make adjustments. Such a process is continuous and includes both reinforcement and revision. The things that work, stay; the things that don't, go.
When the above process is followed within an individual course, the assessment cycle is complete and able to repeat. Instructors can improve at each stage of the process, but the minimum requirements of assessment are being met and modifications (based on assessment data) can be made to improve student learning.
Action can be taken at the program level provided sufficient data have been gathered and checked. If the steps described in the Check stage have been followed, those involved in designing the program can take needed action.
At both the course and program levels, the results of "checking" identify "actions" that will form the basis for subsequent "planning." Action thus allows the Plan-Do-Check-Act cycle to continue.