Synt_Data

Small-scale patterns of the “Arrival City” and ethnic segregation in Vienna

Background and problem definition

For many scientific questions, research institutions and the public only have access to aggregated data sets due to data protection. In order to circumvent the limitations of data aggregation and to ensure data protection, the Vienna Municipal Directorate (MD-OS PIKT) and Municipal Department 23 (Economy, Labor and Statistics) together with the Viennese company MOSTLY AI have carried out a pilot project to synthesize the Vienna Population Register (WBR). The WBR is based on monthly deductions from the Central Register of Residents and includes all Viennese residence registrations. Data synthesisation is an innovative approach to create accessible high-resolution data in an anonymized form. The synthetic data set resulting from the pilot project does not differ in its statistical structure from the original data set, bivariate relationships between different attributes were retained, and at the same time individuals are not identifiable.

Methods and data

To analyse the spatial patterns of the “Arrival City”, the households are located in the respective spatial reference unit (building blocks, census areas, census districts). The Arrival City is identified by variables for the first registration or uninterrupted registration of people in Vienna (“registration_year” and “valid_year”). A differentiation is also made according to country of birth and citizenship: “Vienna group” (no migration background, country of birth Vienna, Austrian citizenship); “federal states group” (country of birth Austria and non-Vienna); “foreign group” (country of birth abroad, non-Austrian citizenship). To analyse the transformation and differentiation of the Gründerzeit city as an Arrival City, the data on new arrivals is linked to data on the housing market segments. For this purpose, the spatial reference units are typologised according to the predominant housing market segment (social housing, Gründerzeit city parified/non parified, new construction, etc.). The focus of interest is primarily on the historic housing stock. Furthermore, the spatial units are differentiated with regard to the average condominium prices. A regression model is used to examine the effect that the transformation of the historic building stock in the past has had on the function of the Arrival City.

To analyse ethnic segregation at different scales, different origin groups are identified based on the variables country of birth (“gebland_1c”) and citizenship (“staat_k1c”). To analyse the effect of the housing market structure on ethnic diversity or segregation, a regression model is set up, which should include, among others, control variables for location or accessibility in the urban area, as well as the spatial variation of condominium prices.

Outcome

The research project has two goals: firstly, it aims to analyse current issues in urban research - Arrival City, Ethnic Segregation - from a small-scale perspective. The empirical analysis at different scales also addresses a classic issue in urban research - the "MAUP" problem (modifiable areal unit problem) - which discusses the distortion of research results (e.g. segregation indices) due to the location and size of spatial units (Lee et al. 2008). Secondly, the applicability of the synthetic population register is to be assessed in terms of its applicability for social science research practice. In a comparison of the results with original data, the strength of the deviation and the change in the accuracy/significance of the synthetic population register with scale (aggregation) are to be assessed.