Table 2 

Calculation of the interobserver agreement (kappa coefficient) 

Pathologist 2 
Total 



1+ 
2+ 
3+ 
1.00 

Pathologist 1 
1+ 
Count (n) 
7 
1 
0 
8 
Pathologist 1 (%) 
87.5 
12.5 
0 
100 

Pathologist 2 (%) 
100 
11.1 
0 
44.4 

% of Total 
38.9 
5.6 
0 
44.4 

2+ 
Count (n) 
0 
8 
0 
8 

Pathologist 1 (%) 
0 
100 
0 
100 

Pathologist 2 (%) 
0 
88 
0 
44.4 

% of Total 
0 
44 
0 
44.4 

3+ 
Count (n) 
0 
0 
2 
2 

Pathologist 1 (%) 
0 
0 
100 
100 

Pathologist 2 (%) 
0 
0 
100 
11.1 

% of Total 
0 
0 
11.1 
11.1 

Total 
Count (n) 
7 
9 
2 
18 

Pathologist 1 (%) 
38.9 
50 
11.1 
100 

Pathologist 2 (%) 
100 
100 
100 
100 

% of Total 
38.9 
50 
11.1 
100 



Symmetric measures 



Value 
Standard error (a) 
Approximate T (b) 
Approximate significance 



Kappa coefficient 
0.906 
0.092 
4.894 
0.00 

Number of valid cases (n) 
18 



a Not assuming the null hypothesis. b Using the asymptotic standard error assuming the null hypothesis. 

Kavanagh et al. BMC Cancer 2009 9:1 doi:10.1186/1471240791 