Simplifying: I want to optimize hiring for integrity, intelligence, and energy.
Vouches and references are helpful in gauging a candidate's integrity, but I want to learn of other approaches that might help filter out people who lack integrity.
The definition of integrity is subjective but that's probably beyond the scope of this post.
-- Warren Buffet
This is what your post is based on, right?
Some managers will be better judges of character than others but as soon as you formalize the process, you also very likely open it up to be exploited by people with low integrity and high intelligence.