**2. Materials and Methods**

Two key elements need to be determined in an examination of the spatial distribution of social inequality: on the one hand, the variables selected as indicators of living conditions and, on the other hand, the territorial aggregations used to analyse them. As mentioned above, in this study we evaluated various indicators related to people's living conditions according to their place of residence in the Catalan territory, and we systematically compared several territorial groupings of the data. The indicators used came from the processing of the Survey of the Population's Living Conditions and Habits (ECVHP) corresponding to the year 2011.

The ECVHP drawn up by the Institut d'Estudis Regionals i Metropolitans de Barcelona (IERMB) and the Institut d'Estadística de Catalunya (IDESCAT) has a five-year periodicity. The 2011 version used here covered the entire territory of Catalonia with an effective sample of 4235 households (sample units) distributed between 529 census tracts,

resulting in a sample of 10,604 individuals (8000 of them aged 16 and over). Sampling errors for Catalonia as a whole were ±1% for individuals and ±1.5% for households. Even though in most cases the sample does not permit any greater disaggregation for statistical exploitation, it is sufficient in size for the purposes of this analysis. A Table S1 indicating the number of records included in each variable and spatial aggregation has been added to the Supplementary Materials to demonstrate the representativeness of the sample. This version was chosen for two reasons: on the one hand, it presents a complete set of data related to residential segregation, as shown more fully below; on the other hand, it evidences the structural nature of territorial inequalities, which was present prior to the crisis situations of the last decade and continued throughout them. Furthermore, although there have been more recent surveys, these do not present a sufficient sample to analyse the whole of the territory of Catalonia and the different territorial aggregations proposed. For details of the methodology of the ECVHPC, see [61]. More specifically, we selected the following five variables (in each, the treatment of the variables and subdivisions of the data responds to the desire to achieve the best possible balance between the sample size of the survey data and the objective of the study):


As mentioned above, these variables have been analysed with respect to four territorial aggregations established according to criteria of: geographical location, population size, intensity of urbanization and social vulnerability. The following four groupings were used for this purpose.


inhabitants; between 50,001 and 100,000 inhabitants; more than 100,000 inhabitants and the city of Barcelona.


These territorial aggregations allow us to classify the population of Catalonia in accordance with the settings and population numbers shown in Table 1 and Figure 1. It should be pointed out that in all the aggregations, the resulting settings present a considerable volume of population (the least populated, Terres de l'Ebre, has 191,631 inhabitants), guaranteeing a suitable level of statistical representativity.


**Table 1.** Distribution of the population according to territorial aggregations. Catalonia, 2011.

**Figure 1.** Territorial settings, Catalonia. (**a**) Planning settings; (**b**) Population size; (**c**) Urban/rural character; (**d**) Residential segregation. Source: In-house construction based on cartography from Institut Cartogràfic i Geològic de Catalunya, inhabitants data from (IDESCAT), Urban/rural character from [14,63] and Residential segregation from [64].
