The theory of change and response: An application to Puerto Rico, 1940 to 1970†

This study demonstrates that even the complex and much misunderstood demographic transition in Puerto Rico can be understood with the aid of the Theory of Change and Response. Analysis of census and vital statistics in Puerto Rico by decade for the rural and urban sectors reveals a wide range of demographic responses. The 1940‘s were characterized by rural/urban migration, urban emigration, and moderate reductions in urban marital fertility. There was no decline in rural marital fertility during the 1940‘s. Contrary to expectations, rural fertility fell very little during the 1950‘s, and the rate of decline of urban fertility was reduced. The decline in the urban general marital fertility rate was smaller than in the 1940‘s (15 against 23 per cent), despite a highly publicized development programme and rapid growth in gross national product. This occurred because there was a ready emigration outlet (to the mainland United States), and because emigration was preferred to a reduction of marital fertility. Emigration to the United States was the dominant response in the countryside, and a major response in the towns, during the 1950‘s. During the 1960‘s vigorous expansion of modern industrial employment led to heavy rural/urban migration, drastically reduced urban emigration, and induced a decline of 30 per cent in urban marital fertility. This study raises many salient issues for the study of fertility and demographic transition in developing countries.