Application of Functional Regression Model on OADR-YADR Relation: The Case of Greece

In the social security system and healthcare system, the process of demographic aging is of major interest. The current research work provides a statistical method based on functional time series regression analysis to improve old-age dependency ratio modeling for the Greek population. The functional time series regression-based model was applied to the old-age dependency ratio and young-age dependency ratio of the Greek population over the years from 1980 to 2023. The estimation of the functional regression model was used to model the relationship between the two age dependency ratios. Therefore, the functional regression model was used to measure the impact of the functional coefficient on young–age dependency ratio and old-age dependency ratio differences. The research findings revealed a varying functional-coefficient with a strong negative function of young-age dependency of the Greek population over the last years. The results confirm a broader usage of the functional regression models to provide more accurate estimates in demography, public health, and age-related policy studies.