Loyalty, commitment proof at job.

The best way to control the way others do their job is within this example:

• Let's see you given routine job like going from door to door within every house
• You provide the list of houses to the person, who gonna do this
• You check random houses by asking its owners whether there was a salesman, or by installing a camera on one of the houses

If the worker haven't appeared at least in one supervised house, it means that his whole job is screwed up because its already means that this employee not visited all of the houses provided.

You'll require report from the employee - why it haven't happened. Next time the employee won't skip any of house, at least if you properly warned that you're always watching and that you're have the ways to control.