Simple and chance-corrected agreements between emergency department (ED) and independent (IND) coders (head to head) in coding external cause of bicycle and pedestrian injuries in the three EDs in Edmonton, Alberta, Canada
| Activity | IND coder | Agreement * | κ statistics† | |||
| a‡ | b | c | d | % | Point estimate (95% CI) | |
| Bicycle injuries | ||||||
| ED coder 2001 (ICD-9) | 58 | 0 | 2 | 60 | 98.3 | 0.97 (0.92 to 1.00) |
| ED coder 2004 (ICD-10) | 57 | 1 | 3 | 59 | 96.7 | 0.93 (0.87 to 0.99) |
| ED coder 2007 (ICD-10) | 53 | 2 | 5 | 60 | 94.2 | 0.88 (0.80 to 0.97) |
| Total and pooled κ | 171 | 0 | 10 | 179 | 97.2 | 0.94 (0.91 to 0.98) |
| Pedestrian injuries | ||||||
| ED coder 2001 (ICD-9) | 23 | 0 | 3 | 94 | 97.5 | 0.92 (0.84 to 1.00) |
| ED coder 2004 (ICD-10) | 15 | 0 | 3 | 102 | 97.5 | 0.90 (0.78 to 1.00) |
| ED coder 2007 (ICD-10) | 21 | 0 | 1 | 98 | 99.2 | 0.97 (0.92 to 1.00) |
| Total and pooled κ | 59 | 0 | 8 | 293 | 97.8 | 0.92 (0.87 to 0.98) |
↵* Agreement=(a+d)/(a+b+c+d).
↵† κ statistics=(probability of agreement) − (probability of by-chance agreement)/1 − (probability of by-chance agreement).
↵‡ a: chart (+) coder (+) or true positive; b: chart (−) coder (+) or false positive; c: chart (+) coder (−) or false negative; d: chart (−) coder (−) or true negative.