Table 2.

Concordance correlation coefficients and related inter-observer agreement statistics for percentage sanitary risk scores recorded by two independent observers for 62 water points in Greater Accra

	Standard WHO observation items	Observation items for urban/peri-urban areas	All observation items combined
Lin’s concordance correlation coefficient (95% confidence intervals)	0.938 (0.901 to 0.962)	0.912 (0.862 to 0.945)	0.949 (0.917 to 0.968)
Pearson’s r	0.952 (p < 0.001)	0.927 (p < 0.001)	0.951 (p < 0.001)
Bias correction factor	0.985	0.984	0.997
Average difference in percent risk scores (95% limits of agreement)	2.95 (− 7.61 to 13.51)	− 2.40 (− 16.83 to 12.04)	0.28 (− 8.26 to 8.83)
Correlation between difference in risk scores and mean	0.107	0.311	0.214
Bradley-Blackwood F test	9.61 (p < 0.001)	6.798 (p = 0.002)	1.58 (p = 0.215)