Table 1. Sample size estimation using the intraclass correlation coefficient based on Giraudeau and Mary.

		Number of participants required for a 95% CI at three confidence levels
Number of observers	Expected ICC	± 0.05	± 0.10	± 0.15
2	0.9	56	14	4
	0.8	200	50	13
	0.7	400	100	25
	0.6	630	158	40
	0.5	865	217	55
4	0.9	36	9	3
	0.8	119	30	8
	0.7	222	56	14
	0.6	322	81	21
	0.5	401	101	26
6	0.9	31	8	2
	0.8	103	26	7
	0.7	187	47	12
	0.6	263	66	17
	0.5	314	79	20
10+	0.9	29	8	2
	0.8	92	23	6
	0.7	164	41	11
	0.6	224	56	14
	0.5	259	65	17

Abbreviations: CI, confidence interval; ICC, intraclass correlation coefficient.

Note: Adapted from Karanicolas et al. ¹⁴