THE SPATIAL DIFFUSION OF FERTILITY - A CROSS-SECTIONAL ANALYSIS OF COUNTIES IN THE AMERICAN SOUTH, 1940

In recent years, the diffusion perspective on variation and change inf ertility levels has attracted increasing interest. Yet, few researcher s have attempted to estimate the effect of diffusion on geographic var iations in fertility. I employ a spatial-diffusion model to assess the effect of diffusion in shaping fertility variation across 1,052 count ies in the American South in 1940. Variation infertility levels and th e ''fertility potential'' for each county are measured. Fertility pote ntial is a spatial-effects variable that summarizes each county's geog raphic proximity to the influence of other high- or low-fertility coun ties. A two-stage least squares technique described by Land and Deane (1992) is used to assess the effect of fertility potential on observed fertility levels. A significant diffusion effect is inferred. The dif fusion effect withstands the introduction of control variables measuri ng a variety of other characteristics of southern counties, many of wh ich, themselves, have significant effects on actual fertility levels. I conclude that inter-county variation in fertility in the South was s haped by a mix of social forces, especially structural and diffusion p rocesses.