I’m in the process of rolling out more stats based on Match Charting Project data across Tennis Abstract. This is the first of what will be several glossaries to explain those stats and point interested visitors to further reading.
At the moment, the following serve stats can be seen at a variety of leaderboards.
- Unret% – Unreturnable percentage. The percentage of a player’s serves that don’t come back, whether an ace, a service winner, or a return error.
- <=3 W% – The percentage of points won by the server either on the serve (unreturnables) or on the third shot of the rally: the “plus one” shot.
- RiP W% – Return in play winning percentage. Of points in which the return comes back, the percentage won by the server.
- SvImpact – Serve Impact. A stat I invented to measure how much the serve influences points won even when the return comes back. The formula used here reflects the average men’s player in the 2010s: unreturned serves, plus 50% of first-serve points won on the server’s second shot, plus 40% of first-serve points won on the server’s third shot, plus 20% of first-serve points won on the server’s fourth shot, all divided by the number of serve points. It is possible to revise the formula for individual players. SvImpact is not included on women’s pages because, on average, the serve has no influence on winner/induced forced error rates for later shots, so it is equivalent to Unret%.
- 1st: SvImpact – Serve Impact on first serves only. Similar to the above, but excluding unreturnable second serves from the numerator and all second serves from the denominator.
- (1st or 2nd) D Wide% – Deuce-court wide serve percentage. Of deuce-court serves that landed in, the percentage that were hit wide. The Match Charting Project divides serves into three categories: wide, middle/body, and T. Rather than listing three percentages for every type of serve, I’m highlighting the percentage of wide deliveries for several classes of serves.
- (1st or 2nd) A Wide% – Ad-court wide serve percentage.
- (1st or 2nd) BP Wide% – Break-point wide serve percentage. I include only break-point serves in the ad court, because a substantial majority of break points take place in the ad court. By omitting deuce-court break points, we can more directly measure whether a player changes serve-direction tactics facing the pressure of a break point.