Basing all of your management decisions purely on statistics is a bad strategy. You're assuming that the weighting of good vs. bad candidate is the same, when they're not.

Hiring a good employee is not nearly as impactful as hiring a bad one. If you can have a strategy that filters out 100% of bad employees, but unfortunately also filters out 90% of good employees, this is preferable to filtering only 50% of good employees, but also only filtering 90% of bad employees. You may have more good employees with the latter strategy, but the bad employees can kill the team.