Forecasting conceptSIKURS - a stream-oriented forecasting model
The forecasting model of SIKURS is based on standard demographic and statistical procedures to project forward a given initial state of the population on the basis of in- and out-migration as well as deaths and births. In this process the SIKURS model calculates population change based on disaggregated streams of change. This is done on the basis of the current demographic conditions of each regional unit in conjunction with population behaviour as determined through an analysis of areas with similar characteristics.
In order to assure the reliability of forecasts for small areas, the individual regional units (e.g. municipal districts) are aggregated into structural types ("area types") on the basis of similarities in behaviour with regard to births, mortality or migration.
Depending on the forecasting variant chosen, different input data are required:
All forecasting variants require essential data for the projection of natural change:
- the initial state of the population for each regional unit either disaggregated by 100 "age years". If desired the age structure can be disaggregated by gender and/or nationality or ethnicity.
- age-specific fertility rates of women according to "area type";
- death rates based on the structure of the initial population.
If, as usually desired, migration is to be included, additional data are required:
- out-migration rates (percent of out-migrants of each demographic group) diaggregated by destinations,
- in-migration from outside the municipal boundaries disaggregated by demographic characteristics.
SIKURS offers many additional forecasting modules, which can be combined in different ways. For instance, variants can run with the input of population and target values for all components of change, the special treatment of new buildings, the deletion of special population groups from the forecast, or the dynamic treatment of birth, death and migration rates. The newest version of SIKURS also makes it possible to include changes in nationality. The"area types" can be created separately for the determination of natural changes, the migration-dependent changes and the changes in nationality.
The SIKURS assistant
The SIKURS-assistant is a dialogue program that helps to compose a version of the forecast model that satisfies the specific requirements of the user. The dialogue makes sure that only a consistent and complete set of modules will be selected.
If required, the main programme of SIKURS examines the input data to ensure that they are complete and plausible. If the data are free of formal errors and of inconsistencies the actual forecast calculations will be carried out, with data output either in the form of monitoring files or on files containing the results. The results can be further processed by other programmes like Excel, Access , SPSS, by mapping programmes or by any other standard software.