The rapidly expanding research literature in comparative state politics typically measures its dependent and independent variables with references to means, averages, and per capitas for each state. (For example, environmental inputs may be expressed as per capita personal income, percent of population living in urban places, median school year completed by the population over 25, etc.; political characteristics may be expressed as average voter turnout levels, percent of the total vote cast for the winning party, etc.; policy outputs are often expressed as per capita expenditures for education, average monthly payments for old age assistance, per capita tax revenues, etc.) With measures such as these, the comparative state politics research has systematically explored many of the linkages between environmental inputs, political system characteristics, and public policy outcomes.
Perhaps the most serious reservation regarding this research is its failure to examine distributive and redistributive aspects of state politics. Both dependent and independent variables are generally expressed as levels or amounts or averages for whole states; these can be neatly arranged for comparative analysis both longitudinally and cross-sectionally. But what about the distribution of wealth within a state? Or the distribution of public monies among high and low income groups, rural and urban populations, or other divisions within a state's population. The linkages between the distribution of resources within states, the distribution of influence within state political systems, and public policies reflecting distributional decisions, remain largely untested.