THE AVERAGE MAN

Evening Post, Volume CXXI, Issue 137, 11 June 1936, Page 29

THE AVERAGE MAN

AGE AND POPULATION

Pick up Dublin and Lotka's recentlypublished "Length of Life" (Ronald) and you discover more about the average man, writes the science editor of the "New York Times." Dr. Louis I. Dublin is . third vice-president, of the Metropolitan Life Insurance Company and Dr. Alfred J. Lotka is assistant statistician of the same company. Each is well-known—rDublin for his many contributions to magazines and his books on population, and Lotka for his "Physical Biology " which broke new ground and which was recommended by the Library Association for the Institute on Intellectual Co-opera-tion of the League of Nations. Both Dublin and Lotka, like other statisticians, hive done much to acquaint us with the now ..familiar and agreeable fact that at birth the expectation of life for a man is 59.31 years. When a male child reaches the age of ten its further expectation is 55.3 years; at 21 it is 45.21 years. The expectation of life of women exceeds that of men by 3.52 years at birth and by somewhat lesser amounts in later years.

Thirty years ago the picture was darker. Then the- average length of human life (the same thing as the expectation of life at birth) was 46.07 years. In a hundred years the gain . haa.-beea~of_ the order. ol 20. years Why the increase? Not one but several' "answers"must be" given'. Dublin and Lotka stress improved standards of living and advances in medical and sanitary science. Especially valuable is the description of' "Applications to Population Problems," which clearly follows the lines laid down by Lotka s Physical Biology." Years ago Lotka showed that a population in which survival and reproduction follow a fixed age schedule ultimately increases at a definite rate different from that which ■ may ' prevail at the' moment. The 'existing and transitoryage distribution which disturbs; the. balance between births and ,deaths gives place to a stable age distribution. The, birth and' death rate is then; characteristic of the actual mortality and -fertility. The priiiciple was first developed by Lotka and Dublin in a notable article published in 1925, now one of the classics of population studies. What does it mean? That the present ex-, ccss of births over deaths is misleading. Actually our rate of reproduction is insufficient in. the long run to balance our mortality despite the increased- expectation of life.