The County Health Rankings are based on a conceptual model of population health that includes both Health Outcomes (length and quality of life) and Health Factors (determinants of health). Health Outcomes include two sub-areas: Length of life and Quality of life. Health Factors include four sub-areas: health behaviors, Clinical care, Social and economic factors and Physical environment. Each of these health outcome and factor areas are composed of individual measures.
Weights for health outcome and factor areas, sub-areas and ranked measures were determined through a process guided by:
- Literature review
- Ability for health factors to be modified through community action
- Review of America's Health Rankings methodology and indicators
- Availability and reliability of nation-wide, county-level data
- Internal analysis
- A panel of technical experts and scientific advisors
County Health Rankings used evidence gathered from the above process balanced with considerations of the interpretability of the model to arrive at a set of weights that reasonably reflect the determinants of health. Additional information is available about the methods used to determine weights (Working Paper on Assigning Determinant Weights).
The County Health Rankings are constructed annually using summary composite scores calculated from the individual measures within the health outcome and factor areas. We calculate and rank eight different summary composites:
- Overall Health Outcomes
- Health Outcomes – Length of life
- Health Outcomes – Quality of life
- Overall Health Factors
- Health Factors – Health behaviors
- Health Factors – Clinical care
- Health Factors – Social and economic factors
- Health Factors – Physical environment
Health Outcome summary score
To calculate the summary score for health outcomes, the scores for Length of life (50%) and Quality of life (50%) combine and sum to 100%. Weights for specific measures were assigned based on theoretical importance within the Health Outcome sub-area alongside considerations of data reliability and availability. Within the Quality of life score, we assign a higher weight 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.
Health Factors summary score
To calculate the summary score for health factors, the following weights are used: Health behaviors (30%), Clinical care (20%), Social and economic factors (40%), and the Physical environment (10%). Like the Health Outcome summary score, weights at each level sum to 100%.
To see the weights for all measures, click here.
Ranking within states
Counties and county equivalents are only ranked within their respective state. County Health Rankings aims to raise awareness about the many factors that influence health, and that health varies from place to place. This goal, and issues that arise with data comparability and availability across states, are the reason that counties are only ranked within their respective state.
Use the compare counties tool to compare counties across the nation and visit these guidelines to learn which measures can be compared across states.