Population forecast
For many years, the city of Jena's small-scale population forecasts have been an indispensable component of our administration's political and economic decisions. The predicted population figures have a significant influence on the design of infrastructure projects, among other things. Based on a precise analysis of previous observations, developments in key demographic factors from the past, such as births, deaths, immigration and emigration, are carried forward into the future. This responsible task was assigned to our statistics office by resolution 12/1855-BV in the mayor's official consultation. After 2014, the second small-scale population forecast has now been carried out under the leadership of the Controlling and Statistics team using the SIKURS program of the KOSIS network (KOSIS-Kommunales StatistischesInformationssystem).
Kleinräumige Bevölkerungsprognose 2019
A group of experts, consisting of representatives
- of the departments "Finance, Security & Citizen Services", "Urban Development & Environment" and "Family, Education & Social Affairs",
- the Jena Economic Development Agency,
- the Thuringian State Office for Statistics and
- TIMOUROU - housing and urban space concepts,
discussed in three premise rounds the extent to which the trends of recent years will continue and whether changes are to be expected. The discussions led to the assumptions of the most likely population development up to the year 2035. The SIKURS software was used to implement these assumptions and subsequently calculate the forecast. The result is referred to as the real case or main variant and is based on the city's population register data for people with their main place of residence. This data is available for the city as a whole and the six planning areas (Lobeda, Winzerla, East, North, West/Centre and localities).
In addition, bandwidths were explored with the help of scenarios that show the extent to which deviating developments are conceivable. These resulted in a best case and a worst case with regard to population development. This introduced a methodological change compared to the 2014 population forecast, in which deviating developments were determined using an error corridor based on ex-post forecast quality measures.
The real case scenario was also expanded to include people with a registered secondary residence. The results of this population forecast are in turn the basis for the forecast of statistical private households (household forecast).
Prognose/Ist-Vergleich
Since the forecast was prepared with 2018 as the base year, there have now been 7 comparative years (2019 to 2025). During this time, there have been several exogenous shocks, some of which have counteracted the forecast data.
The coronavirus pandemic was responsible for a decline in the population due to fewer new arrivals and excess mortality. The influx of people seeking protection as a result of the war in Ukraine temporarily led to an increase in the population again. This was followed by an unforeseeable collapse in the birth rate. Future studies will certainly examine the extent to which the economic situation of families due to the development of energy prices and inflation had an impact on their desire to have children.
Our dashboards for comparing actual and forecast figures compare the most important indicators for the city as a whole and the six planning areas at a glance and show trends. This data is collected annually with the population statistics and then published under Downloads. Important results for the city of Jena as a whole are listed below.
- Forecast error -2.1 %
- after an interim population increase in 2022, population decline again in 2023, 2024 and 2025
- the age groups aged 30 and over were slightly overestimated
- positive development of the age groups 6 to under 18 years and 18 to under 30 years
- Slump in the 0 to under 6 age group due to repeated sharp drop in birth rates
- Surplus of deaths (647 births to 1,213 deaths)
- Positive migration balance
- Continuous increase in the average age since 2018 from 42.7 years by one year to currently 43.8 years
Haushalteprognose 2019
The 2019 household forecast provides an overview of the future development of statistical private households up to 2035. It is based on the population forecast for the real case with secondary residences in conjunction with the annual household generation procedures using the HHGEN software from the KOSIS association. This method does not take dormitories, shared accommodation etc. into account. In a forecast/actual comparison, it must be noted that the annual household figures are slightly overstated. This is due to people who are registered as having a secondary residence in Jena and who have not deregistered after moving away (unregistered persons).
As a result, the number of statistical private households will increase by 2,081 to 63,133, while the average number of persons per household will decrease from 1.78 at present to 1.74 in 2035. Further information can be found under Downloads in the short report on the household forecast.