Zasępa, Ryszard2017-12-312017-12-311981Ruch Prawniczy, Ekonomiczny i Socjologiczny 43, 1981, z. 4, s. 187-1970035-9629http://hdl.handle.net/10593/21157Model life tables can be generated according to the hypothesis of W. Brass by acceptance of an adequate table as standard one and by using the formula (1). The possibility was then examined of using such tables for mortality forecasting. Tables generating a system, by which the tables are generated, depends upon two parameters α and ß, interpretation of which has been described. Model tables closeness has been examined on the ground of existing life tables for Poland by town and villages when (I) the life table 1970 - 1972, or (II) an average of the life tables 1960-1961 and 1970 - 1972 were taken as a standard. Differences in real values lx and in values from model tables occured. An example has been given for men in Table 1, and results have been shown. The results rx occur systematically and runs are created by their signs. Forectasting that is based on model tables delivers biased forectasts. It can be significantly diminished by taking into account the biases estimated from the past data. Such a forecast has been done experimentally in two variants for the year 1980. In the variant I in estimation of parameters α and ß data for age-groups x=1, 5, 10, 15, ..., 85 years have been taken into account, and for the variant II data for the years x=1, 75, 80, 85 have been omitted. Differences in expectation of life at age x, ex have been presented in Table 2, and in Table 3 — death pro probability nqx within the interval (x, x+n) for both forecasts variants. Comparisons lead to the conclusion that both variants are too optimistic, and the projection obtained from variant II is relatively more relevant. The data for the last one are presented in Table 4. Expectation of life at age x, ex and death probability have been compared in Tables 5 and 6, for the years 1970, 1973,1976 and the projection 1980, respectively. The necessity of the Brass model extension to more than two parameters is stated in the conclusion. Further studies will shown, whether proper modifications lead to more realistic mortality projection.polinfo:eu-repo/semantics/openAccessArtykuł