Parallel convergence of income and educational achievements on a local level in Poland : joint distribution dynamics

In the last decade, after accession to European Union, Poland has achieved a significant improvement of indicators relating to income on a national level. Polish GDP per capita (in PPP terms) increased from 49% of European Union average in 2004 to 67% in 2013 showing progress in each year (source: Eurostat). Simultaneously an impressive progress was achieved by Polish secondary schools pupils, which is confirmed by international comparisons of educational results (PISA). Empirical analyses of GDP per capita distribution and its dynamics on a regional level in Poland show that the above mentioned progress does not spread out proportionally on all regions and income convergence is not observed. Instead, the relatively fastest growth of initially richest regions (mostly large cities) introduces convergence of clubs which leads to polarization. The purpose of the research is to analyze the relationship between the local convergence of income and educational achievements on a local level in Poland in the period 2003-2013. We aim to verify if and how the convergence processes of these two phenomena are related to each other. The analysis is applied on the level of municipalities (LAU 2, former NUTS 5). Income is measured in terms of per capita revenue in municipality budget from the share in receipts from personal income tax (source of data: Local Data Bank, Polish Central Statistical Office). Educational achievements are measured by the median results of standardized lower-secondary school leaving exams (source of data: Polish Central Examination Board). We introduce a concept of parallel convergence as a way of measurement of the co-relationship between the two phenomena. The evolution of the joint distribution of income and educational achievements is analyzed with the use of a transition matrix generalized for the two-dimensional distributions and with two dimensional kernel density estimates. The analysis shows that in regions with initially highest relative income also initial educational achievements are usually equal to or higher than the average for the whole country. In the regions with relatively lowest initial income the initial distribution of educational achievements does not differ from its distribution for all municipalities. The joint distribution is relatively stable over time. Initial analysis of the dynamics of the joint distribution between 2003 and 2013 shows that for regions with initially lowest income the probability of improving low exam results is lower than the probability of becoming relatively richer. The largest mobility of the joint distribution was observed for the groups with the lowest or low initial income and the highest educational achievements, while highest persistence was found for the groups initially richest with high or the highest educational achievements.