RallyIQ

WTA · Right-handed · 2 charted matches · 2022–2022

Catherine Harrison

Shot expected value

The share of points Catherine Harrison goes on to win after each option in the positions they face most often, shrunk toward tour average when the sample is small. Showing the 8 most-used options; teal marks the best one with at least 30 shots.

Rally, shots 5–8: drive to your middle

position worth 50% to the average player · 40 shots

OptionUsedWin %Tour
FH through the middle 28% 48.9%±14.8 45.8%
BH down the line 25% 46.7%±15.0 50.0%

Serve under pressure

Deuce court

1st serveUsageBreak ptWon when in
Wide 20% 0% ▼ 68% / 66%
Body 49% 0% ▼ 59% / 57%
T 30% 100% ▲ 72% / 68%

69 normal · 2 break-point 1st serves

Ad court

1st serveUsageBreak ptWon when in
Wide 35% 27% 59% / 66%
Body 27% 33% 46% / 56%
T 38% 40% 74% / 64%

52 normal · 15 break-point 1st serves

Is the serve mix in equilibrium?

Game theory says a well-mixed server wins equally often with every direction they use. If one direction wins more, it's underused and points are being left behind. This is the minimax test Walker and Wooders ran on Wimbledon finals, applied to every charted first serve. Win rates include faults. "Optimal" allows for returners reading a habit. A direction loses 0.19 points per 100 serves for every 10 points of habitual usage, measured from WTA servers whose mix drifted between matches. Shifts stay within the range servers' habits actually vary, the only range that response was measured over.

Deuce court

1st serveUsagePoints won
Wide20% 61.6%±12.1 n=14
Body48% 61.0%±10.0 n=34
T32% 63.5%±10.9 n=23

Consistent with an optimal mix (p = 0.91).

Ad court

1st serveUsagePoints won
Wide33% 42.6%±11.3 n=22
Body28% 36.0%±11.3 n=19
T39% 58.7%±10.8 n=26

Off equilibrium (p < 0.001): serve T more. Gap 11.7 points per 100 first serves.

Return by serve direction

Return points won against each serve direction, compared with the tour average.

ServeCourtDirectionPointsWonvs tour
1stAd courtBody 11 37% −6.9±12.4
1stAd courtT 1 34% −1.1±14.0
1stAd courtWide 16 36% +1.1±11.6
1stDeuce courtBody 17 42% −0.5±11.8
1stDeuce courtT 17 35% +3.3±11.5
1stDeuce courtWide 3 31% −3.1±13.2
2ndAd courtBody 7 58% +3.1±13.3
2ndAd courtT 3 56% +1.1±14.2
2ndAd courtWide 3 55% +1.2±14.3
2ndDeuce courtBody 8 51% −3.6±13.3
2ndDeuce courtT 1 57% +1.4±14.6
2ndDeuce courtWide 2 57% +2.9±14.4

Charted matches