of neonatal death may not account for all of this wide variation in the neonatal mortality rate; some variation may be due to higher rates of underreporting of neonatal deaths.
Most authors presume that registration of mortality in the Russian Federation, the Baltic states, and the other former Northern republics is complete. Anderson and Silver (1990, 1991, and in this volume), however, have analyzed regional mortality patterns in the former Soviet Union and concluded that there is substantial underregistration of adult deaths in the former Central Asian republics. To date, judgments that there has been substantial underreporting of deaths in certain republics have been based solely on the fact that observed mortality rates appear to be too low. Such assessments presuppose that the determinants of relative levels of adult mortality within the former Soviet Union or among industrialized countries are known. For example, Anderson and Silver (1990, 1991) report lower age-specific mortality in Tajikistan than in the United States for males; in the age groups over 70 years, the differences are as high as 20 to 50 percent. The authors conclude that lower adult mortality in Central Asia than in the United States is "implausible," although they provide no epidemiological justification for this judgment.
Studies of adult mortality patterns (ages 15-59) in industrialized and developing countries have demonstrated wide variations in adult male and female mortality as measured by 45q15—the probability of death between ages 15 and 60. For example, in Japan, male 45q15 is 113 per 1,000, compared with 175 per 1,000 for all U.S. males, 300 for U.S. black males, and 187 for Finnish males (Murray et al., 1992). Given the wide range in adult mortality levels that is not easily explained by variables such as income per capita, it is not convincing to argue that there is significant underregistration in Central Asian states solely because their observed rates are lower than those of other states.
To define further the extent of underregistration in different states of the former Soviet Union, we use the growth balance method and the Bennett-Horiuchi technique (United Nations, 1983). We apply the growth balance method using registered deaths in 1989 and the census population for 1989 by age for each republic. Application of this method depends on having a population that approximates a stable population with a long-term constant birth rate and no net migration. The relationship between Nx/Nx+ and Dx+/Nx+, however, is not linear for almost all republics; Nx is the population at age x, Nx is the population over age x, and Dx+ is deaths over age x. The age group "birth rate," Nx/Nx+, is markedly lower for the age groups 70-74 and 75-79 for most republics, which may reflect the World War II experience of this cohort. Excluding these age groups and 80+ years, the estimated coverage for the former Soviet Union com-