The impact of the applied typology on the statistical picture of population ageing in urban areas in Poland – a comparative analysis

The aim of the paper is to review and compare the processes of population ageing in Polish urban areas. The study presents a novel approach to the problem, because in addition to measuring this phenomenon according to the National Official Register of the Territorial Division of the Country (TERYT) classification, it also measures population ageing according to the classification for urban areas (LAU 2 units) - Degree of Urbanisation (DEGURBA). Several traditional demographic measures for population ageing were applied, such as the median age, parent support ratio, ageing index, elderly dependency ratio, share of people aged 65 and older, and total dependency ratio. Also, Chu's alternative measure of population ageing accompanied by a dynamic version of ageing index was computed. The values of these indicators for 2016 were compared with those for 2010. The authors carried out a more detailed analysis of the differences between the ageing of populations in urban areas according to the degree of urbanization (DEGURBA), and compared the outcome with the results of the TERYT-based measurement (the traditional administrative territorial division). The comparison of the outcomes of both the above-mentioned ways of measuring the phenomenon of population ageing showed discrepancies, namely the ageing process measured according to the DEGURBA typology proved to be less intensive than the same process assessed according to the TERYT typology. This indicates that there are differences between the statistical pictures of population ageing in urban areas depending on whether demographical and morfological aspects are taken into consideration or not.