On the convergence of Das Gupta's model of fertility projection.

A regression model expressing the age-specific fertility rates at a given point of time as a variable dependent upon the same at the preceding points of time has been developed by Das Gupta for purposes of fertility projection. The model, judged by the values of the multiple correlation coefficients, appears to work very well with the U.S. data set, and it also produces limiting values of the fertility rates when the projection is carried far into the future. The conditions of convergence of such a model have been determined in this paper according to which the model's usefulness for purposes of long-term projection of fertility rates appears to be severely restricted.