Table 2. Differences between win rates for Level 1 game elements observed over three periods.

Level 1	1970-2000 (1)	2001-2015 (2)	2016-2021 (3)	(1) vs. (2)		(1) vs. (3)		(2) vs. (3)		χ2	P<	Ccorr
	n=9300	n=5410	n=4984	h-Cohen	p*	h-Cohen	p*	h-Cohen	p*
1. Serve	12.52%	9.63%	8.27%	-.092	<.001	-.140	<.001	-.048	.015	372.9	.001	.154
2. Serve+Counterattack	19.88%	21.16%	20.47%	.032	.062	.015	.407	-.017	.381
3. Return	16.20%	14.36%	15.13%	-.051	.003	-.030	.093	.022	.271
4. Return+Counterattack	12.06%	14.71%	14.39%	.078	<.001	.069	<.001	-.009	.636
5. Attack+Counterattack	17.14%	17.01%	16.35%	-.004	.835	-.021	.231	-.018	.372
6. Block+Counterattack	9.87%	7.43%	7.54%	-.087	<.001	-.083	<.001	.004	.826
7. Push+Counterattack	3.20%	4.64%	8.55%	.074	<.001	.133	<.001	.159	<.001
8.Attack-against-chop+Counterattack	2.92%	4.71%	4.01%	.094	<.001	.060	.001	-.034	.081
9. Chop+Counterattack	2.26%	3.18%	2.25%	.057	.001	-.001	.967	-.058	.004
10. Other	3.94%	3.16%	3.05%	-.042	.016	-.048	.007	-.006	.744

h-Cohen – the value of h Cohen indicator (effect size), p* - statistical significance at p<0.017, χ² – the value of chi-square test, p – the significance of χ² test, C_corr - corrected contingency coefficient.