Skip to main content

Table 2 Injury / death status, and estimated regression coefficients for non-modifiable, non + semi-modifiable, and non + semi+modifiable risk factors to predict the risk of injury or death in a farm crash: 2005–2010

From: Public health application of predictive modeling: an example from farm vehicle crashes

Variables Categories Injured or died Model coefficients (std. error)
Yes No Model 1a Model 2b Model 3c
Intercept Intercept (constant) 2087 12,747 −1.75 (0.18) −1.73 (0.24) −0.97 (0.25)
Non-modifiable factors
 State Iowa 421 1858 0.39 (0.10) 0.46 (0.10) 0.42 (0.10)
Illinois 421 2230 0.19 (0.10) 0.20 (0.11) 0.33 (0.11)
Kansas 186 1291 −0.19 (0.12) −0.21 (0.12) − 0.26 (0.13)
Minnesota 199 1688 −0.30 (0.11) −0.24 (0.12) − 0.08 (0.12)
Missouri 207 1686 −0.09 (0.11) −0.21 (0.12) − 0.34 (0.12)
North Dakota 51 431 −0.43 (0.21) −0.50 (0.21) − 0.56 (0.21)
Nebraska 189 970 0.16 (0.12) 0.11 (0.12) 0.08 (0.12)
South Dakota 74 379 0.16 (0.17) 0.14 (0.18) −0.06 (0.19)
Wisconsin (referent) 339 2214 0 0 0
 Season Winter (Jan-Mar) (referent) 192 1510 0 0 0
Planting (Apr-May) 341 2307 0.06 (0.12) 0.20 (0.12) 0.17 (0.12)
Growing (Jun-Aug) 635 3492 0.30 (0.11) 0.42 (0.11) 0.38 (0.11)
Harvesting (Sep-Dec) 919 5438 0.19 (0.10) 0.16 (0.10) 0.15 (0.10)
 Weather at the time of crash Clear (referent) 1618 9802 0 0 0
Cloudy 329 2081 −0.01 (0.08) − 0.09 (0.08) − 0.11 (0.08)
Rain 78 376 0.17 (0.15) −0.03 (0.16) 0.03 (0.16)
Snow/sleet/hail/freezing rain/drizzle 22 289 −0.74 (0.28) −0.89 (0.28) − 0.87 (0.28)
Fog/smog/smoke/other 40 199 0.15 (0.22) 0.01 (0.22) −0.08 (0.23)
 Time of crash 12:00–5:59 am (referent) 131 739 0 0 0
6:00–11:59 am 501 3478 −0.11 (0.13) 0.13 (0.14) 0.17 (0.14)
12:00–5:59 pm 885 6218 −0.14 (0.13) 0.08 (0.13) 0.08 (0.14)
6:00–11:59 pm 570 2312 0.41 (0.14) 0.12 (0.14) 0.11 (0.14)
 Number of vehicles Single vehicle 238 827 1.37 (0.10) 1.22 (0.13) 1.22 (0.14)
Two or more vehicles (referent) 1849 11,920 0 0 0
 Equipment type Farm vehicle/equipment 672 6875 −1.14 (0.06) −1.02 (0.06) −1.63 (0.08)
Non-farm vehicle (referent) 1415 5872 0 0 0
 Age <  16 years age 159 799 0.24 (0.11) 0.04 (0.13) 0.13 (0.14)
16–24 years age 388 2120 0.24 (0.09) 0.21 (0.09) 0.22 (0.10)
25–34 years age (referent) 234 1839 0 0 0
35–44 years age 288 1851 0.15 (0.10) 0.15 (0.10) 0.20 (0.10)
45–54 years age 325 2326 0.11 (0.09) 0.10 (0.10) 0.13 (0.10)
55–64 years age 278 1794 0.22 (0.10) 0.24 (0.10) 0.30 (0.10)
65+ years age 415 2018 0.49 (0.09) 0.51 (0.09) 0.59 (0.10)
 Sex Female (referent) 626 2663 0 0 0
Male 1461 10,084 −0.19 (0.06) −0.14 (0.06) −0.26 (0.06)
Semi-modifiable factors
 Light Daylight (referent) 1407 10,195   0 0
Dark-street lights on 27 223   −0.20 (0.25) −0.27 (0.26)
Dark-no street lights 553 1882   0.57 (0.10) 0.59 (0.10)
Other 100 447   0.50 (0.14) 0.42 (0.15)
 Manner of collision Non collision (referent) 294 1301   0 0
Head-on 127 415   0.40 (0.17) 0.40 (0.18)
Rear-end 716 2747   0.28 (0.13) 0.28 (0.13)
Angle, oncoming left turn 361 2343   0.04 (0.14) 0.10 (0.14)
Sideswipe, same direction 192 2698   −0.85 (0.15) −0.73 (0.16)
Sideswipe, opposite direction 152 1462   −0.65 (0.16) −0.55 (0.16)
Other 245 1781   −0.21 (0.14) −0.21 (0.14)
 Vehicle action Heading straight (referent) 1510 6934   0 0
Turning 133 2489   −0.55 (0.11) −0.62 (0.11)
Overtaking/ passing/ changing lanes 280 1750   −0.25 (0.09) −0.34 (0.10)
Slowing/stopping 43 608   −0.89 (0.17) −0.84 (0.18)
Other 121 966   −0.30 (0.11) −0.35 (0.11)
 Multiple passengers No (referent) 1392 9908   0 0
Yes 695 2839   0.28 (0.08) 0.34 (0.08)
 Driver No (referent) 433 1710   0 0
Yes 1654 11,037   −0.16 (0.09) −0.08 (0.09)
Modifiable factors
 Driver contributing circumstance No contributing action (referent) 871 6508    0
Disregarded traffic regulation 302 1487    0.35 (0.09)
Reckless, careless, negligent, aggressive driving 407 2510    0.16 (0.08)
Inattentive/distracted driver 256 1093    0.25 (0.09)
Other contributing action 251 1149    0.25 (0.10)
 Occupant Protection None (referent) 870 4534    0
Seat belt 1052 7439    −1.19 (0.09)
Child safety restraint 59 384    −1.25 (0.20)
Other restraint/ protection 106 390    0.18 (0.16)
Quasi-likelihood Information Criterion (QIC) 10,844.4 10,077.4 9676.8
AUC (95% CI) 0.69 (0.68, 0.71) 0.75 (0.74, 0.76) 0.78 (0.76, 0.79)
  1. Abbreviations: AUC Area under the receiver operating characteristic (ROC) curve
  2. amodel 1 includes non-modifiable factors
  3. bmodel 2 includes non-modifiable and semi-modifiable factors
  4. cmodel 3 includes non-modifiable, semi-modifiable, and modifiable factors