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. 2012 Feb 12;21(8):1508–1515. doi: 10.1007/s00586-012-2184-4

Table 2.

Estimates of intra-rater reliability

Reliability N measurements Thickness Thickness change
ICC (±95%CI) SEM (mm) SDD (mm) ICC (±95%CI) SEM (%) SDD (%)
Intra-rater 2 1 0.95 (0.93–0.97) 0.30 0.83 0.56 (0.30–0.74) 15.36 42.57
2 (mean) 0.97 (0.95–0.98) 0.22 0.62 0.75 (0.52–0.87) 10.99 30.47
3 (mean) 0.97 (0.95–0.98) 0.22 0.62 0.81 (0.65–0.90) 9.06 25.12
Intra-rater 5 1 0.86 (0.75–0.92) 0.48 1.34 0.34 (−0.96–0.67) 18.91 52.43
2 (mean) 0.96 (0.93–0.98) 0.25 0.68 0.71 (0.30–0.89) 10.47 29.01
3 (mean) 0.97 (0.95–0.99) 0.22 0.60 0.84 (0.60–0.94) 7.28 20.18

Presented are intraclass correlation coefficient (ICC: ±95% confidence interval; models: 2,1 for single measurements 2,2 for two repeated measurements, and 2,3 for three repeated measurements), standard error of measurement (SEM) and smallest detectable difference (SDD). Intra-rater reliability 2 describes reliability of measurements performed with a 2-day break (i.e. Monday–Wednesday, Wednesday–Friday); intra-rater reliability 5 describes reliability of measurements performed with a 5-day break (i.e. Monday–Friday) (see Fig. 1)