Class boundaries are conceived as properties of a multiple system of stratification,
composed of several rank systems. In each system, the same population is ranked by
a different criterion of status. The central question in boundary analysis is: To
what extent are the incumbents of any two contiguous ranks of one rank system separated
in another? The magnitude of a class boundary is measured by the degree of such separation.
This method is applied to the population of Detroit and is used in testing alternative
predictions derived, respectively, from "class structure" and "status continuum"
hypotheses. The findings suggest that each of these hypotheses is appropriate to
a different range within the same stratification system.