The ATP World Tour Finals has a unique tournament structure with 2 groups playing round robin followed by a 4 person tournament. Simulation of this becomes tricky as there are multiple tiebreaker scenarios within the round robin portion of the tournament. These tiebreakers include head-to-head wins, percentage of sets won, percentage of games won, and ATP ranking. Simulation of this event therefore requires not only W/L of the matches but also the score line. Fortunately, the Riles Clubhouse serve, return, and tiebreak efficiencies can be used to do just this.
Using the aforementioned specific efficiencies, I am able to simulate the odds each player holds serve against the simulated opponent. Then the match can be simulated one game at a time, utilizing the tiebreak efficiencies should the set end 6-6. I then do this for all matches from the round robin to the final knockout tournament. Utilizing a Monte Carlo simulation, I then simulate the tournament thousands of times to determine the chances for each player for their group standing all the way to the odds they win the championship.
Since the tournament has already begun, I have included both the original and updated odds. The original below shows the odds before the matches began on Sunday and the updated show the odds with the 1st set of matches completed.
Updated through 11/16