Table 1.

Intraobserver–intramethod reliability

	Mean difference between two measurements (°)	P valuea	Pearson’s correlation coefficient	95%-C.I.b (°)
Spike method
O-I	0.04	0.846	0.962	±2.1
O-II	0.08	0.809	0.903	±3.3
Fin method
O-I	−0.08	0.692	0.955	±2.0
O-II	−0.04	0.894	0.916	±3.0

O-I experienced observer 1, O-II inexperienced observer 2

^aPaired t test

^b95% Confidence interval around the mean difference