The first life table

Abstract

To two Fellows of the Society, John Graunt (elected 1663) and Edmond Halley (elected 1678), the world owes the invention of that powerful vital-statistical instrument, the life table or table of mortality, but the respective shares of these men in the discovery is a matter of dispute. In the first edition of Graunt’s famous ‘Natural and Political Observations mentioned in a following Index and made upon the Bills of Mortality' (p. 84 of fifth edition), which secured his admission to the Society, Graunt included a short table purporting to give the survivors of 100 quick conceptions at the end of 6, 16, 26, 36, 46, 56, 66, 76 and 86 years. The Bills of Mortality in Graunt’s time did not record ages at death, and he reached the second entry in his table, viz. 64 survivors at the age of 6, by a rough classification of the named causes of death into those which wholly affected children (thrush, convulsion, rickets, etc.), and those of which he thought about half (small pox, swine pox, etc.) affected children below the age of 6. The remaining figures are conjectural. Some statisticians hold that Graunt had discovered the principle that, under certain conditions, a survivorship table could be computed from a summation of deaths in age groups; others believe that the table is a mere guess and not even Graunt’s but a contribution to his book from his friend William Petty. There is no doubt that, as an instrument of computation, the table is of little value.