Table 1.

Measures of central tendency, reliability, and effect sizes for Level A clinical concussion measures

SAC	n	Mean (SD)	Median	1st quartile	3rd quartile	ICC (lower, upper bound)	Cohen’s d
Year 1	3208	27.25 (2.03)	27	26	29	0.39 (0.36–0.42)	0.07
Year 2		27.39 (1.91)	28	26	29
Year 1	372	27.25 (1.99)	28	26	29	0.34 (0.24–0.42)	0.42
Year 3		28.01 (1.65)	28	27	29

BESS	n	Mean (SD)	Median	1st quartile	3rd quartile	ICC (lower, upper bound)	Cohen’s d
Year 1	2894	13.15 (6.06)	12	9	17	0.41 (0.38–0.44)	0.28
Year 2		11.50 (5.57)	11	7	14
Year 1	323	11.95 (5.58)	11	8	15	0.42 (0.32–0.50)	0.24
Year 3		10.65 (5.46)	10	7	14

SCAT: total symptoms	n	Mean (SD)	Median	1st quartile	3rd quartile	Kappa	Cohen’s d
Year 1	4360	0.79 (0.77)	1	0	1	0.40	0.10
Year 2		0.71 (0.74)	1	0	1
Year 1	581	0.72 (0.74)	1	0	1	0.42	0.05
Year 3		0.72 (0.78)	1	0	1

SCAT: symptom severity	n	Mean (SD)	Median	1st quartile	3rd quartile	Kappa	Cohen’s d
Year 1	4360	0.98 (1.04)	1	0	2	0.41	0.11
Year 2		0.88 (0.98)	1	0	1
Year 1	581	0.86 (0.96)	1	0	1	0.41	0.05
Year 3		0.87 (1.00)	1	0	1

BSI-18	n	Mean (SD)	Median	1st quartile	3rd quartile	ICC (lower, upper bound)	Cohen’s d
Year 1	4328	2.67 (4.80)	1	0	3	0.38 (0.35–0.40)	0.13
Year 2		2.09 (4.50)	0	0	2
Year 1	551	2.52 (4.05)	1	0	3	0.51 (0.44–0.57)	0.19
Year 3		1.80 (3.73)	0	0	2

BESS balance error scoring system, BSI brief symptom inventory, ICC intraclass correlation coefficient, SAC standardized assessment of concussion, SCAT standardized concussion assessment tool, SD standard deviation