The County Health Rankings (CHR) measure the health of nearly all counties in the nation and rank them within the state they reside. The Rankings are compiled using county-level measures from a variety of national and state data sources. These measures are standardized and combined using scientifically-informed weights.
To calculate the ranks, each measure is first standardized. Measures are selected based on their technical and analytical feasibility, ensuring they are not limited by availability, cost, validity, coverage, or other concerns. The ranks are then calculated based on weighted sums of the standardized measures within each state. The county with the lowest score (best health) gets a rank of #1 for that state and the county with the highest score (worst health) is assigned a rank corresponding to the number counties ranked in that state. Counties are only ranked within their respective state, relative to the health of only other counties in the same state.
The Rankings are based on summary composite scores calculated from the individual measures. Eight different summary composites are calculated and ranked:
1. Overall Health Outcomes
- 2. Health Outcomes - Length of life
- 3. Health Outcomes - Quality of life
4. Overall Health Factors
- 5. Health Factors - Health behaviors
- 6. Health Factors - Clinical care
- 7. Health Factors - Social and economic factors
- 8. Health Factors - Physical environment
To calculate the summary score for Health Outcomes, the scores for Length of life (50%) and Quality of life (50%) were combined. The weights for specific measures were assigned based on relative importance within the factor. Within quality of life, a higher weight was assigned to the low birthweight measure since this measure is based on a census of all live births whereas the other measures are based on a survey of a sample of the population.
To calculate the summary score of health factors, the following weights were used: Health behaviors (30%), Clinical care (20%), Social and economic factors (40%), and Physical environment (10%). The weights for specific measures were also assigned based on relative importance within the factors.
To learn more about rankings methods, please review publications with more details on CHR's site here.
Methodology information sourced from the CHR site's methods pages.