Table 3.

Intra-and inter-observer kappa values for semi-quantitative estimates of tumour stroma ratio

	N	Kappa values (TSR: 4-groups)	Kappa values (TSR: High/Low)	Weighted kappa (TSR: 4 groups)
TSR-A1 & TSR-A2	129	0.68, p < 0.001	0.83, p < 0.001	0.77, p < 0.001
TSR-A1 & TSR-A2	43	0.65, p < 0.001	0.78, p < 0.001	0.75, p < 0.001
TSR-A1 & TSR-B	50	0.45, p < 0.001	0.75, p < 0.001	0.64, p < 0.001
TSR-A2 & TSR-B	50	0.47, p < 0.001	0.70, p < 0.001	0.67, p < 0.001

Tumour stroma ratio was estimated semi-quantitatively by conventional microscopy. Intra-observer kappa values were calculated for all sections (n = 129) and the deepest invasive tumour section (n = 43), and inter-observer kappa values were calculated for 50 randomly selected sections. Kappa values were calculated for data expressed in four groups; TSR-4-groups (1: TSR > 75%, 2: 50% < TSR ≤ 75%, 3: 25% < TSR ≤ 50%, 4: TSR ≤ 25%) and data expressed in two groups; TSR high/low (high TSR = stroma ≤50% and low TSR: stroma > 50%)

Abbreviations: TSR tumour stroma ratio; A1 First count by observer A; A2 second count by observer A; B count by observer B