Principles are ways of successfully dealing with reality to get what you want out of life.
Ray Dalio, one of the world’s most successful investors and entrepreneurs, cites principles as his key to success.
Develop a full profile of each person's values, abilities, and skills. These qualities are the real drivers of behavior, so knowing them in detail will tell you which jobs a person can and cannot do well, which ones they should avoid, and how the person should be trained. These profiles should change as the people change.
If you don't know your people well, you don't know what you can expect from them. You're flying blind and you have no one to blame but yourself if you don't get the outcomes you're expecting.