Measurement and data source for county-level variables
| Variable | Measurement | Source | Year |
| Rural/urban | Binary | US Department of Agriculture, Office of Rural Health Policy | 2010 |
| Percentage Black | Continuous | US Census American Community Survey | 2014 |
| Percentage Hispanic | Continuous | US Census American Community Survey | 2014 |
| Percentage over 65 | Continuous | US Census American Community Survey | 2014 |
| Percentage male | Continuous | US Census American Community Survey | 2014 |
| Poverty rate | Continuous | US Census American Community Survey | 2014 |
| Percentage no high school diploma | Continuous | US Census American Community Survey | 2014 |
| Unemployment rate | Continuous | US Census American Community Survey | 2014 |
| Active medical doctor rate | Continuous | Health Resources and Services Administration | 2014 |
| Opioid pills dispensed rate | Continuous | Epidemiology Resource Center, Indiana State Department of Health | 2014 |
| Halfway house provider rate | Continuous | National Directory of Drug and Alcohol Abuse Treatment Programs | 2014 |
| Buprenorphine provider rate | Continuous | National Directory of Drug and Alcohol Abuse Treatment Programs | 2014 |
| Naltrexone provider rate | Continuous | National Directory of Drug and Alcohol Abuse Treatment Programs | 2014 |