Introducing migratory flows in life table construction

Abstract

The purpose of life tables is to describe the mortality behaviour of particular groups. The construction of general life tables is based on death statistics and census figures of resident populations under the hypothesis of closed demographic system. Among other assumptions, this hypothesis implicitly assumes that entries (immigrants) and exits (emigrants) of the population are usually not significant (being almost of the same magnitude for each age compensating each other). This paper theoretically extends the classical solution to open demographic systems and studies the impact of this hypothesis in constructing a life table. In particular, using the data of residential variations made available to the public by the Spanish National Statistical Office (INE, Instituto Nacional de Estadística) to approximate migratory flows, we introduce in the process of constructing a life table these flows and compare, before and after graduation, the crude mortality rates and the adjusted death probabilities obtained when migratory flows are, and are not, taken into account