Table 2.

Performance of different classification models.

	Both groups				National tennis players				International tennis players
	AUC	CA	Se	Sp	AUC	CA	Se	Sp	AUC	CA	Se	Sp
Server	0.686	0.215	0.201	0.214	0.834	0.453	0.577	0.526	0.901	0.575	0.575	0.575
Returning player	0.953	0.664	0.735	0.664	0.970	0.780	0.801	0.780	0.883	0.642	0.710	0.642
Return category	0.667	0.523	0.595	0.523	0.717	0.581	0.621	0.581	0.753	0.549	0.583	0.549

AUC, area under the curve; CA, classification accuracy; Se, sensitivity; Sp, specificity are presented for classifying individual server, returning player, and return category for all returns combined and for returns made by national and international tennis players separately.