Table 1

Inter-rater reliability for stroke sub-type, demographic, clinical features, and pre-hospital data.

Variable (Item Number)
Dichotomous response option
N
PI*
Kappa (95% LCL)†
BI‡

Coverdell stroke sub-type (1.0)
Ischemic Stroke
104
0.24
0.61 (0.46)
-0.07

Intracranial hemorrhage (ICH)
104
-0.86
0.93 (0.79)
0.01

Subarachnoid hemorrhage (SAH)
104
-0.89
0.90 (0.72)
0.01

Transient ischemic attack (TIA)
104
-0.64
0.70 (0.52)
-0.01
Gender (1.2)
Female
104
0.16
0.98 (0.94)
0.01
Race (1.3)
White
104
0.40
0.55 (0.38)
0.13

Black or African American
104
-0.66
0.97 (0.90)
0.01

Not documented (missing)
104
-0.76
0.07 (-0.13)
-0.11
Health Insurance status (1.7)
Medicare
104
0.43
0.83 (0.72)
0.03

Medicaid
104
-0.86
0.50 (0.18)
- 0.03

Self-pay
104
-0.89
0.52 (0.15)
0.01
Arrival mode (2.2)
Ambulance
104
-0.40
0.82 (0.69)
0.00

Other
104
-0.14
0.59 (0.43)
-0.01

Hospital transfer
104
-0.74
0.70 (0.50)
0.03

Not documented (missing)
104
-0.72
0.40 (0.15)
-0.01
Direct admit (2.2b)
Yes
98
-0.88
0.47 (0.17)
0.04

* Prevalence Index (PI) is a measure of the true prevalence of the trait. PI is 0 when concordant responses are equally balanced between the 2 raters. A large negative PI indicates trait is rarely found, while a large positive PI indicates trait is common. Variables with extreme distributions i.e., PI < -0.90 or > 0.90 are not shown. 95% LCL = 95% Lower Confidence Limit.

Bias Index (BI) is a measure of the relative bias between the hospital and audit abstractors. BI is 0 when there is no bias. Positive BI values indicate a bias toward the hospital abstractor, negative BI values indicates a bias towards the audit abstracter. BI values > 0.10 or < -0.10 indicate substantial bias.

Reeves et al. BMC Neurology 2008 8:19   doi:10.1186/1471-2377-8-19