Producing reliable mortality estimates in the context of distorted population statistics: the case of Moldova

Background and Aim Despite having a functioning population register, the official demographic indicators in Moldova are seriously biased. The problem arises primarily because the registration of deaths and births covers only the events that occur within the country (the de facto population), whereas the population at risk includes Moldovan citizens who live abroad (the de jure population). Because the country has high levels of emigration, there are substantial differences between the de facto and the de jure population numbers. Thus, the nominator-denominator bias must be taken into account in the population statistics. To obtain plausible demographic rates, appropriate corrections of population size have to be made. Our aim is to estimate the size of the de facto Moldovan population, and to produce reliable mortality estimates for the longest period possible. Data and Methods We rely on official data obtained from various sources. These include mortality data, census counts, and annual population estimates collected from archives or obtained directly from the Moldovan National Bureau of Statistics. Using alternative administrative data sources, we first correct the size of the Moldovan population. We then generate adjusted population estimates. Finally, on the basis of the adjusted population estimates, we produce life tables. All of the calculations are performed using the methodology and programming tools developed within the Human Mortality Database (HMD) Project. Results Our corrected population estimates are 18 percent lower than the official figures. The adjusted estimates of life expectancy at birth in 2014 are 64.94 years for males and 73.74 years for females. These figures are, respectively, 2.58 years and 1.65 years lower than the official estimates. Our estimates of the size of the population are consistent with unpublished 2014 population census data. Complete life tables for the period 1970–2014, as well as some other HMD statistics, are provided as supplementary material. Conclusions We show that even when there is a serious distortion of population statistics, it is possible to obtain plausible mortality estimates. This issue is highly relevant not just for Moldova, but for other European countries that have also been experiencing problems with the incorrect registration of migration. To improve the quality of their population estimates, countries will increasingly have to consult alternative administrative data sources.