Quality Assurance: Rater Performance
The extent of agreement between the 2 raters measured using the Cohen κ statistic was “almost perfect” (κ=0.81-1) for the rating scheme items 1, 2, 4a, 4d-13, and 15-18. The extent of agreement on items 14 complied with “substantial agreement” (κ=0.780), items 3 and 4c with “moderate agreement” (κ=0.41-0.60), and item 4b with “slight agreement” (κ=0.077). All values were significantly different from zero (