| Abstract: | Estimates of mortality rates and expectation of life at birth, using infant mortality rates, are examined on the basis of 150 life tables for both sexes. Least squares linear estimates are given as well as estimates of their variances. Model life table calculations, as proposed by the U.N. Population Branch, are then compared with these unbiased minimum variance estimates and shown to overestimate the expectation of life by more than two years on the average, and to be at most 68% efficient. Though better estimates are provided in this paper, their variance is still so large as to cast doubt on the practical usefulness of anv estimates based exclusively on infant mortality rates. |
