Table 3.

Interobserver reliability by spinal cord level. Reported values are κ values

Grades	C4–5	C5–6	C6–7	Overall
Park system	1.000 (1.00–1.00)	0.911 (0.829–0.993)	0.922 (0.818–1.00)	0.913 (0.856–0.970)
Kim system	0.662 (0.422–0.902)	0.750 (0.620–0.880)	0.808 (0.662–0.937)	0.769 (0.688–0.851)
Modified Kim system	0.921 (0.777–1.000)	0.803 (0.680–0.926)	0.839 (0.710–0.968)	0.823 (0.745–0.902)

Strength of interobserver agreement (κ) was characterized as follows: poor (k < 0.1), slight (0.1 ≤ k ≤ 0.2), fair (0.2 < k ≤ 0.4), moderate (0.4 < k ≤ 0.6), substantial (0.6 < k ≤ 0.8) and almost perfect (0.8 < k ≤ 1).

Data: values in parentheses are 95% confidence intervals.