I can tell a win or loss just from champ select with ~90% accuracy.
If my team plays less overpowered champions than the enemy team I can pretty much guarantee a loss. If my team plays more overpowered champions than the enemy team i can basically guarantee a win. Good job with the balance Greg "ghostretard" Street! Glad Riot hired you to ruin your third game!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!