For many years, the small-scale population forecasts of the city of Jena have been an indispensable part of political and economic decisions of our administration. Among other things, the projected population figures have a significant influence on the design of infrastructure projects. On the basis of a precise analysis of previous observations, developments of essential demographic factors from the past, such as births, deaths, inflows and outflows, are transferred into the future. This responsible task was assigned to our statistics office by resolution 12/1855-BV in the Lord Mayor's official consultation. After 2014, the second small-scale population forecast was carried out under the leadership of the Controlling and Statistics team using the SIKURS program of the KOSIS network (KOSIS-Communal Statistical Information System).
Small-scale population forecast 2019
A group of experts, consisting of representatives
- of the departments "Finance, Security & Citizen Service", "Urban Development & Environment" as well as "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 rounds of premises to what extent trends of recent years will continue and whether changes are to be expected. The discussions led to the assumptions of the most probable population development until the year 2035. The software SIKURS was used to implement these assumptions and then to calculate the forecast. The result is referred to as the real case or main variant and is based on the municipal population register data of persons with main residence. These are available for the city as a whole and for the six planning areas (Lobeda, Winzerla, East, North, West/Centre and localities).
In addition, scenarios were used to explore bandwidths 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 by means of an error corridor based on ex post forecast quality measures.
For the real case scenario, an expansion was also made to include persons with registered secondary residences. The results of this population forecast are in turn the basis for the forecast of statistical private households (household forecast).
The first forecast year, 2019, has come to an end. Time to draw a comparison between the expected and the actual population development. For this reason, we have developed dashboards that compare the most important indicators for the city as a whole or the six planning areas at a glance and show trends. These data are collected annually with the population statistics and are always published in the first quarter under Downloads. The most important results for the entire city of Jena are listed below.
- Forecast error -0.3
- largest deviations in the planning area Lobeda -1.1 %
- all age groups slightly overestimated
- first population decline since 2002 for the city of Jena
- first death surplus since 2005 for the city of Jena
- negative migration balance due to overestimation of inflows and underestimation of outflows
- largest increase in the age group 80 years and older
- renewed increase in the average age
Household forecast 2019
The household forecast 2019 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 procedure does not take into account residential homes, shared accommodation and the like. In a forecast-actual comparison, it must be noted that the annual household figures are slightly overstated. This is due to persons who are registered in Jena with a secondary residence and have not deregistered after moving away (deadbeats).
As a result, the number of statistical private households increases by 2,081 to 63,133 with a simultaneous decrease in the average number of persons per household from currently 1.78 to 1.74 in 2035. Further information can be found under downloads in the short report on the household forecast.