Question 1

What is VOPO in tennis betting?

Accepted Answer

VOPO (Value Over Pinnacle Odds) is the difference between Tennis Glicko's internal win probability (average of Glicko-2 and Elo models) and the implied probability from Pinnacle's odds. A positive VOPO means the market is undervaluing a player.

Question 2

What is Green EV in tennis betting?

Accepted Answer

Green EV is Tennis Glicko's high-conviction value signal. It triggers when VOPO exceeds 12% AND the internal win probability is above 50% — indicating the market is significantly mispricing a player.

Question 3

How accurate is Tennis Glicko?

Accepted Answer

Tennis Glicko has 72.8% predictive accuracy over the last 30 days, with a Brier Score of 0.1775 — a standard probabilistic calibration metric used in forecasting.

Question 4

Why use Glicko-2 instead of ATP rankings for tennis predictions?

Accepted Answer

ATP rankings are a lagging indicator — they ignore surface specialization, injury returns, scheduling fatigue, and form swings. Glicko-2 updates after every match, adjusts for opponent quality, and models rating uncertainty, making it significantly more accurate for predicting match outcomes.

Daisuke Sumizawa

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