How to deal with sub-national forecasts in spatially very heterogeneous countries?

1. How to deal with sub-national forecasts in spatially very heterogeneous countries? Towards using some spatial theories and models Can demographers make RPF without assistance of geographical approaches? Bleha Branislav Comenius University in Bratislava Vaňo Boris Demographic Research Centre in Bratislava

2. Importance of regional and local forecasts Borrowed from Mai, Bucher 2005

3. Importance of fegional and local forecasts Borrowed from Population Atlas of Slovakia, 2006

4. Importance of fegional and local forecasts • The RPF are not in the core of demographers ´ interest • What are the possible reasons? • Results at national level are more visible and popular for the public, media • as well as for decision makers • Difficulties in making them methodological sophistication • sophictication of the assumptions • demographers vs geographers

5. Issue of appropriate method Rogers (1975, 1995), Rees (1983), Willekens – Drewe (1984), Rees – Convey (1984), Plane – Rogerson (1985), a. o. Which of these methods have been systematically used so far by official bodies making regional forecasts? And...What is the probability they would be used in near future? Not a quite new dispute over Methodological improvement Vs Improvement of ability to „decode“ the future (postulate assumptions as aptly as possible)

6. Issue of appropriate method Borrowed from Keilman – Kučera 1991

7. Issue of appropriate methods Population size Population size Percentage Error (PE), 6 years after starting point Evaluation of the Slovak Statistical Office ´s Forecast 1994 Source: Bleha 2007

8. Convergence or divergenceat European level? • Why the convergence, why not the divergence? • What are the arguments for...? Do we have any? • Is Europe so strongly coherent demographic system of interconnected elements (=countries) in which we should necessary look at such processes? • Is the the general convergence within Europe „efficient“ for homogenisation of demographic processes? • If absolute convergence of TFR comes, why at levels 1,5-1,6, why not at current levels of the Nordic countries and France? • How to express the migration convergence? (no migration or zero net migration or identical numbers in the matrix of net migration flows from/to pairs of regions?

9. Fertility from the spatial point of view CONVERGENCE or DIVERGENCE? Are the regions of Slovakia heading towards convergence? Fertility clusters Although principally, the best way is to create assumptions individually for each region, yet we decided to use Ward´s cluster method to group the districts into clusters and then make forecasts for these clusters

10. Fertility divergence at subnational levelSearch for some empirical arguments Spatial spread of natural decrease using isochrons Note: The isolines depict the first year the surplus of deaths occurred Indirect evidence of spatial spread of demographic behaviour Originally published in Mládek - Bleha (2001) See alsoThornton and Philipov (2007) – developmental idealism...

11. Fertility divergence at subnational levelSearch for some empirical arguments Fertility in 2025 ..“Timing of the pioneer regions can partly serve as a pattern for modelling of timing of conservative regions“...Spatial autocorrelation

12. Migration from the spatial point of view • Wide analysis of geographical approaches (macro-position factor in Slovakia resulting in division into „wealthy“ south-west and a „poor“ north-east) • Will the regional convergence come or not? If yes, when and to what extent? Slovak as well as European demographers are not offered a satisfactory forecast on regional differentiation by regionalists, who have not concluded whether the regional differences will keep on growing, or if they are to decelerate or even decrease in future. • If perfect convergence among regions comes, what level of economic migration will remain? No one? Half of current level? Else one? To what extent regional development does force the demographic one? • Using spatial polarisation? (Woodward 1995, Badcock 1997, a. o.)

13. Modelling the future demographic heterogeneity of regions • Assumptions vs results • To what extent does the convergence of the assumptions lead to the convergence of results? Effect of age-structural momentum (no. of potential mothers etc...) NUTS IV regions Bratislava

14. Modelling the future demographic heterogeneity of regions Lowering disparities among calibrated parameters of regions will not necessarily result in lower disparities among regional results

15. Modelling the future demographic heterogeneity of regions Fixating the recent character and level of fertility would lead to sharper decrease of number of births (birth rates), but just to a moderate increase of variability of values. (model I) Modelling bigger differences among TFR values = Increasing changes in reproductive behaviour across regions DO NOT LEAD to an extreme growth of variability of births in future. This fact indicates, that the most of the future variability (of births) can be explained by the age-structural momentum effect. (model III) According to scenario model no. IV, all regional populations would record identical values of fertility (as whole SVK). In spite of this, the variation coefficient of number of births would drop only slightly.

16. Conclusion • The more attention should be paid to this topic, because of direct and indirect effects of demographic diversity on regional disparities • Geographical approaches are neccessary to be used in making regional forecasts • The role of spatial theories is serious • The regional demographic convergence is probably coming, however, only in a very long-term view because The same demographical behaviour for all Slovakia ´regions (EUROPEAN regions) would not lead to the uniform population change at all (due to age-structural diversity being much higher than that at national level