You are 100% correct. As a manager I would love to test for work ethic, honesty, being a team-player, etc. The problem is I can only infer those qualities based

You are 100% correct. As a manager I would love to test for work ethic, honesty, being a team-player, etc. The problem is I can only infer those qualities based on signals that are inherently noisy. The only way you really know of those qualities is by working with them over a period of time. A solution to this is to hire through your network, especially via someone who has worked with the candidate. But that certainly limits your pool.