Notes on methodology from 2015, Methodological explanations

European cities face a variety of challenges, ranging from population ageing, through migration and urban sprawl, to counteracting climate change. On the other hand, Europe's dynamic cities attract investments, people and services, thereby stimulating creativity and innovation. Cities are seen as both the source of and solution to economic, environmental and social challenges. Therefore, cities are central to achieve the Europe 2020 targets: smart, sustainable and inclusive growth.

Statistics on urban and rural areas measure economic, social and environmental issues and provide information, based on which different analyses can be carried out. For example, certain data are used to identify which areas have the highest risk of unemployment, the highest proportion of population aged 65 and above, or the highest concentration of employment within a particular activity.

Areas and regions can be categorised according to the degree of urbanisation. Based on population size and density, they indicate if an area is a:
1. rural area (thinly populated area)
2. town or suburb (intermediate density area)
3. city or urban area (densely populated area).

Following the above and considering the quality of published data, different data from various administrative and statistical sources were used. Most often, the data of the Croatian Bureau of Statistics were used.

Data sources for the production of subnational statistics can be grouped as follows:
  • data collected by the Croatian Bureau of Statistics
  • data taken over from state bodies and other bodies with public authorities.

The selected cities were Zagreb, Rijeka, Slavonski Brod, Osijek, Pula, Zadar and Split. Zagreb, the capital city, has a population of more than 250 000 inhabitants, while the population of other cities ranges between 50 000 and 250 000 inhabitants. All cities together cover approximately 32% of the total population of the Republic of Croatia.

It should be noted that there were some deviations from the default definitions in the production of subnational statistics. For example, the municipality of Okrug is a part of the functional urban area Split, although it does not share a land border with other parts of the functional urban area. However, the municipality of Okrug is located on an island and shares a sea border with other parts of the functional urban area.

Concerning economic activity, until 2016, a work-based definition of job was used and data were collected from the Statistical Business Register instead from the employment and wages statistics and the Labour Force Survey. Since 2017, small area estimates have been used for economic activity.

Functional urban areas around selected cities were selected as follows: it was determined for every city if the daily commuting rate was over 15% (according to the 2011 Census data) within municipalities and towns at the local administrative unit LAU2 level and then continuous functional urban areas (no holes or gaps) were created.

Functional urban areas were created by the Croatian Bureau of Statistics only for the needs of subnational statistics on the basis of the nearest neighbourhood criterion. Such a delimitation of areas in the Republic of Croatia covers more than 500 towns and municipalities, which are a good basis for the construction of a homogenous functional urban area.

The number of units of sub-city district (SCD) units ranges between 9 and 22. The population for identified units varies between 3 992 and 70 009 inhabitants (per SCD in Zagreb). There were more than 5 000 inhabitants in three sub-city districts according to the 2001 Census, but less than 5 000 inhabitants according to the 2011 Census.

The data referring to the variables “number of dwellings connected to potable drinking water supply system” and “number of dwellings connected to sewerage treatment system” are in fact data on the state of being connected to potable drinking water supply system and sewerage treatment system. It is impossible to estimate the number of connected households in the Republic of Croatia, since more than one of them (in some cases even hundreds of dwellings) use the same connection to the water supply system. The situation is similar in most European countries. When comparing the data set from 2013 and 2014 to the data set from 2015 to 2019, it should be noted that the definition referring to the population connected to potable drinking water system and the population connected to sewage system has been changed.

The methodology for urban statistics, based on which subnational statistics were prepared, is available in the Methodological Manual for City Statistics, while the collected data for cities, functional urban areas and sub-city districts as well as local committees are available in the Subnational Statistics Database.

All data published on the website of the Croatian Bureau of Statistics have been approved by Eurostat and are available in Eurostat’s database under the category Cities (Urban Audit).
Notice: The subnational statistics project is continuously carried out in cooperation with Eurostat.