Throughout the publication, regional disparities in different domains are analysed through the persistence of disparities across regions and cities over space and time. More precisely, the report proposes several approaches to measure regional disparities:
The straightforward difference between the maximum and minimum regional values in a country (regional range).
Ranking regions by the value of an indicator and taking the ratio (or the difference) between the highest value representing 20% of the population and the lowest value of the regions representing 20% of the population. This approach assesses regional disparities that are less sensitive to possible outliers and cross-country differences in the size of regions.
Using standard composite indices, such as the Theil general entropy index, which reflects inequality among all regions.
Summarising spatial disparities by type of territory. This includes using the degree of urbanisation or OECD typology on access to cities in small administrative regions (Territorial Level 3, TL3).
The cut-off date for data included in the publication was 8 September 2024. Due to the time lag of subnational statistics, the last available year is generally 2023 for demographic and labour market and 2022 for socio-economic indicators.