Table II.

Interobserver agreement

	X-ray	2D CT	3D CT	3D models
Overall (consultants and registrars, n = 14)
kappa
κ	0.29	0.30	0.35	0.47
95% CI	0.26-0.31	0.27-0.33	0.33-0.38	0.44-0.50
Agreement∗	Fair	Fair	Fair	Moderate
P value†	<.001	<.001	<.001	<.001
% agreement
%	57.2	57.8	58.8	66.5
95% CI	55.1-59.3	55.5-60.2	56.7-60.9	64.6-68.4
Number of images	30	29	28	26
Consultants (n = 7)
kappa
κ	0.26	0.37	0.30	0.48
95% CI	0.20-0.32	0.31-0.43	0.24-0.36	0.42-0.55
Agreement	Fair	Fair	Fair	Moderate
P value	<.001	<.001	<.001	<.001
% agreement
%	56.0	62.9	57.1	66.8
95% CI	50.2-61.9	56.3-69.4	52.0-62.3	62.3-71.3
Number of images	30	29	30	27
Registrars (n = 7)
kappa
κ	0.35	0.25	0.39	0.51
95% CI	0.29-0.40	0.19-0.31	0.34-0.45	0.44-0.57
Agreement	Fair	Fair	Fair	Moderate
P value	<.001	<.001	<.001	<.001
% agreement
%	60.3	54.1	60.1	68.3
95% CI	57.3-63.4	49.0-59.3	55.1-65.0	64.4-72.3
Number of images	30	30	28	29

2D, two-dimensional; 3D, three-dimensional; CI, confidence interval; CT, computed tomography.

^∗Agreement has been defined using the Landis and Koch criteria (Table I).²⁰

^†P value less than .05 shows that kappa was statistically significantly different from “0”.