Table 1.

RMSE of the difference between each observer and the reference for each direction; p‐value of Student's t‐test for each direction putting together all data for each group is reported in the last column

	Observers Group 1						Observers Group 2
	1	2	3	4	5	$RMS\pm SD$ (all data Group 1)	6	7	8	9	$RMS\pm SD$ (all data Group 2)	p
LR (mm)	2.3	1.2	1.9	1.8	1.4	$1.32\pm 1.74$	3.0	2.7	2.8	2.2	$2.67\pm 2.68$	$<0.01$
SI (mm)	2.3	1.0	1.3	1.8	1.7	$1.69\pm 1.65$	3.4	3.5	3.0	3.1	$3.24\pm 3.22$	$<0.01$
AP (mm)	1.9	1.9	1.9	2.3	2.3	$2.05\pm 2.06$	3.6	3.0	2.6	3.0	$3.09\pm 2.70$	$<0.01$