SPRING 2026

AUTHORS

Aiwen Li, University of Pennsylvania 
Amrita Balajee, University of Pennsylvania 
Harry Wieand, Boston University Academy
Jonathan Pipping-Gamon, University of Pennsylvania 

ABSTRACT

Traditional tennis rating systems (e.g., Elo) summarize overall player strength but do not isolate the independent value of serving. Using point-by-point data from Wimbledon and the U.S. Open, we develop serve-specific player metrics that separate serving quality from return ability and other latent factors. For each tournament and gender, we fit logistic mixed-effects models of point outcomes using serve speed, speed variability, and placement features, with crossed server and returner random intercepts to capture unobserved player strengths.

From these models we derive Server Quality Scores (SQS): partially pooled, opponent-adjusted estimates of players’ serving impact. In out-of-sample evaluation, SQS aligns more strongly with serve efficiency—the probability of winning points within three shots—than weighted Elo. We further benchmark SQS against task-aligned serve-stat baselines and model ablations, quantifying the incremental value of serve features and partial pooling.

Associations with overall serve win percentage are smaller and dataset-dependent, and neither SQS nor weighted Elo consistently dominates that outcome. Overall, SQS is best interpreted as a measure of serve-induced short-point advantage (serve quality plus early-point conversion), complementing holistic ratings with actionable insight for coaching, forecasting, and player evaluation.