SURVIVAL RATIO IN LIFE TABLES

Abstract

In the usual life table the number of survivals lx at age x, starting from the original number l0, 100, 030 or 10, 000 at birth is tabulated. If we designate the ratio lx+n/lx x 100 (n=1, 2, 3, ) as survival ratio, this indicates the proportion of persons reaching (x+n) years of age among persons who reached x years of age. And the magnitude of this ratio depends on the magnitude of deaths in the age interval between x and (x+n). If persons in the age interval are healthy, the number of deaths would be small, and the ratio lx+n/lxwould consequently be large. Hence the ratio may serve as an adequate indicator of the healthiness of persons in that age interval.From this point of view, all kinds of ratios were computed using six Life Tables of Japanese so far published, x being changed from 0 to 80, and n from 1 to 90.An abstract of the result is shown in Table I and II anddepicted in Fig. I-V. How the ratios change with age and interval may be clearwithout any further explanation.