The Ecology of Chicago: Persistence and Change, 1930-1960

Two sets of factor analyses are performed upon census data for Chicago from 1930 to 1960. The first method explores changes in ecological structure by comparing four separate factor analyses, each done at a different point in time. The second method explores the structure of ecological change and is based upon the factor analysis of differences in variables over three time periods. The first method reveals a marked stability in Chicago's ecological structure, with important changes being a decline in explanatory power of the family-status factor, a rise in explanatory power of the racial-ethnic factor, and the linkage of age and racial-ethnic segregation in the city. These findings are related to propositions in the factorial ecology literature. The second method reveals highly variable factors of change from one decade to the next, which appear to reflect unique societywide changes occurring in each period. The methods are briefly compared. In general, the first method most clearly elucidates stable and persistent ecological structure, while the second method is more sensitive to short-run ecological change taking place within the established structure.