Abstract Studies which examine social mobilility across two generations often find relatively small fluctuations in the amounts of mobility experienced by parents and their grown children. Among nations, by contrast, there are often substantial differences in rates and amounts of mobility. One possible explanation for both of these patterns is that mobility rates are tied to stages of economic development. Because development levels do not ordinarily change during short intervals of time, rates of mobility between generations tend merely to undergo relatively minor fluctuations. However, because there are substantial variations in economic development among nations, cross- national rates of social mobility are also quite variable.. Contemporary surveys can not directly test the mobility- development thesis, even if they ask respondents' recollections, because they can not collect data over a sufficently long period of time. In recent years, however, sociologists and social historians have put together a number of data sets on mobility in the United States during the nineteenth and early twentieth century. They cover a sufficient period of time to permit the investigator to examine long term trends. (The birth cohorts in the disaggregated data range from l776 to l952.) The analysis involves re-coding the occupational placements of respondents into the same categories so that mobility can be measured in comparable occupational terms in all of the data sets. In addition to examining the mobility-development thesis, the data sets permit analysis of both racial and regional differences in mobility in the United States during this 150 year period.
