Table 2.
Random-effects Summary Odds Ratios and 95% Confidence Intervals of Crash Involvement Associated With Marijuana Use, by Study Characteristics
| Study Characteristic | OR | 95% CI |
| Study design | ||
| Case-control | 2.63 | 1.87, 3.71 |
| Cohort | 2.04 | 1.36, 3.07 |
| Cross-sectional | 3.61 | 2.37, 5.49 |
| Type of drug assessment | ||
| Self-report | 2.93 | 2.07, 4.17 |
| Blood or urine test | 2.26 | 1.46, 3.49 |
| Study time period | ||
| Before 2000 | 2.82 | 1.77, 4.50 |
| 2000 and after | 2.58 | 1.89, 3.53 |
| Study location | ||
| North America | 2.97 | 2.13, 4.14 |
| Other | 2.31 | 1.59, 3.35 |
| Age of study subjects | ||
| <25 years | 3.03 | 1.83, 5.01 |
| All ages | 2.50 | 1.81, 3.46 |
Abbreviations: CI, confidence interval; OR, odds ratio.