Health 'disparity' is a current public policy issue. This creates possibilities for public discussion of dynamics that stratify population health status. A short review of current discussion in public health and sociology is used to create a conceptual framework for factors that influence disparities, namely dominance, disorder and isolation. The framework provides the basis for a system dynamics 'concept model'. Work in progress on the model is outlined. The model is to be used when discussing ways in which local civic action can reduce health disparities.