Table 2. SIGMA-VB: two-rater chance-corrected agreement coefficients (quadratic-weighted).

Instrument/week	Correlation coefficient	Standard error of the mean	95%CI	p-value
Cohen’s kappa
0	0.90	0.02	0.86-0.94	< 0.001
1	0.95	0.01	0.93-0.97	< 0.001
2	0.95	0.01	0.93-0.97	< 0.001
4	0.93	0.02	0.88-0.98	< 0.001
8	0.98	0.00	0.97-0.99	< 0.001
Scott’s pi
0	0.90	0.02	0.86-0.94	< 0.001
1	0.95	0.01	0.93-0.97	< 0.001
2	0.95	0.01	0.93-0.97	< 0.001
4	0.93	0.02	0.88-0.98	< 0.001
8	0.98	0.00	0.97-0.99	< 0.001
Brennan-Prediger
0	0.94	0.01	0.93-0.96	< 0.001
1	0.97	0.01	0.96-0.98	< 0.001
2	0.97	0.00	0.96-0.98	< 0.001
4	0.95	0.02	0.91-0.98	< 0.001
8	0.99	0.00	0.98-0.99	< 0.001
Gwet’s AC2
0	0.95	0.01	0.93-0.96	< 0.001
1	0.97	0.00	0.96-0.98	< 0.001
2	0.97	0.00	0.96-0.98	< 0.001
4	0.95	0.02	0.92-0.98	< 0.001
8	0.99	0.00	0.98-0.99	< 0.001
Krippendorff’s alpha
0	0.90	0.02	0.86-0.94	< 0.001
1	0.96	0.01	0.94-0.97	< 0.001
2	0.95	0.01	0.93-0.97	< 0.001
4	0.93	0.02	0.88-0.98	< 0.001
8	0.98	0.00	0.97-0.99	< 0.001

95%CI = 95% confidence interval.