In recent years a growing body of research has used multivariate statistical techniques to examine the relationship between aggregate environmental characteristics and the public policies of state and local governments. This research has been concerned primarily with isolating or demonstrating the social, economic, and political correlates of either public policies (e.g., expenditures, revenues and referenda issues) or governmental structures (viz., form of government, size of election districts and type of ballot).
One advantage of the aggregate approach, beyond the relative accessibility of data, is that it permits a systematic, comparative study of states or cities. On the local level this comparative approach provides a convenient supplement to the earlier case study approach which was concerned with the political processes and issues of particular cities.
A number of hypotheses have been suggested by studies employing either the case study or aggregate approaches. In those observations dealing with government structure, attention is usually directed to the council-manager plan as an example of progressive government. That is, city governments which are reform-oriented are likely to be found in more affluent, better educated, homogeneous, middle-class cities. The notion is that the middle class prefers a more efficient, professional city administration. Conversely, the mayor-council plan is usually associated with older, machine-type politics which allegedly reflects the preferences of the less affluent, less-educated, working class and ethnic minorities who are most concerned about political representation.