Common questions
Why not give your best collectors every account?
For: Owner, operations
It's the obvious move, and most floors run a version of it: rank the collectors, give the strongest ones first pick. It helps, and it has a ceiling.
Your best collectors run out of hours. A top collector can only work so many accounts a day. Send everything good to her and the rest still goes to whoever is next.
"Best" is an average, and an average hides specialists. Split the floor by type of account and the order changes: a collector who looks middling overall can be your strongest on aged, low-balance accounts. Route by rank and you spend her on accounts anyone competent would have closed, while the accounts that needed her go elsewhere.
BestPair works at the level of the pair. It asks which accounts each collector does best with, judged from your own history, and sends each one to that collector inside the group your routing already chose. Work spreads across the floor instead of piling onto the top few.
And it can't be gamed by cherry-picking. Accounts are split at random, so easy ones land in the control group at the same rate. The extra can't come from giving your best collectors the easy work.