Table 2.

Diagnostic accuracy and error range of the estimation of colon polyp size

	Visual estimation	Forceps estimation	P value
Diagnostic accuracy
Beginners	0.613	0.734	< 0.001
Experts	0.680	0.784	< 0.001
Total	0.639	0.754	< 0.001
Error range (mm)
Beginners	1.68 ± 1.30	1.38 ± 1.08	< 0.001
Experts	1.42 ± 1.11	1.12 ± 1.11	< 0.001
Total	1.48 ± 1.18	1.20 ± 1.10	< 0.001