Evaluation of the Effect of Changing Population Age Structures on National Saving in Iran

One of the important macroeconomic variables is national savings. National saving can be affected by several factors, one of these factors is population age structure. Scientific and quantitative determination of the impact of population age structure on national saving is an important issue that is discussed in this paper. In this study relied on Ando and Modigliani's life-cycle hypothesis, has been analyzed the effect of population age structure transitions on national saving in Iran. For this purpose, a model is proposed to explain the national saving and demographic variables included in the model and coefficients have been estimated using an Auto Regressive Distributed Lag Model (ARDL). National savings model consists of two equations, one of the equations represents the long-run equilibrium relationship and other indicates short-run dynamic. In addition, the method of error correction is used for determining the adjustment speed of dynamic model toward long run equilibrium. Annual time series data for the period 1984-2016 have been used. The findings show that the population age structure is an effective factor in formation of the national savings. Increasing the proportion of people in the age group 20 to 24 years reduces national saving. Against, increasing proportion of population aged 25 to 54 years, will increase in national savings. Most of the savings made by the group aged 35-44 years. On the other hand, the increase of population in the age group 55 years and more, again, reduces national saving.