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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