From LinkedIn

Inspection or control?

Inspection is comparable to a post-mortem examination: it is meaningless for the person on whom it is performed, and not very meaningful for others either, unless it is used constructively to help cure those who are currently ill (hopefully before they are "inspected" too!).

Control is like a health check (for example before a race, to assess whether you can run without getting injured): it would also be meaningless unless its results were quickly used and reflected in the next execution.

Sometimes an "inspection plan" is confused with a "control plan": the first looks at the effect (the output), while the second looks at the causes, ensuring that all the variables (which are "variable", indeed!) take the "correct" value when the process is performed.

Both "can" be useful, but control lets you make much more money!

P.S. If your process doesn't make any money, you'd better try to get rid of it rather than improve it!