These notes raise questions about the economic consequences of demographic trends, consequences in terms of what the trends imply for the rate of economic advance and for the distributive aspects of economic growth. These are questions rather than answers, for lack of firm basis for the latter; and even the questions are selective. The two trends chosen for comment are: the long-term decline in birthrates, associated largely with increasing control of intramarital fertility; and the long-term rise in the proportion of population in advanced ages (65 and over), associated largely with the recent impact of health technology in reducing mortality at the higher ages.

The natural concentration in Professor Easterlin's paper on the recent, forty-year swing in fertility, left little room for noting the underlying downtrend. Yet it is conspicuous in Easterlin's table 4.A.1, from the 1870s to World War II; and even within the swing itself, the average birthrate declined, from 22.3 per thousand in the four quinquennia of 1935–55 to 19.5 per thousand in the twenty-three years from 1955 to 1978. The consensus of the present projections suggests further decline. According to the latest, 1978, assessment (medium variant) by the United Nations, the average for 1955–60 to 1975–80 (the latter weighted by half) of 19.8 per thousand will drop to an average of 15.8 for 1975–80 (weighted by half) through 1995–2000.