Central Statistical Office of Poland Information Portal

The division of cities into sub-city districts (SCD)

SCDs were determined on the basis of:

1. Division into statistical units;
2. The coefficient of location, referred to also as Florence’s concentration

• it allows the assessment of a spatial concentration degree within territorial arrangement units and also an insight into the size of existing disproportions (deviation value),
• the modified version of this coefficient was used; in a simplified version, the coefficient of location calculated for the surveyed (selected) group is subtracted from the total population of the whole city and from the total population of a given spatial unit.

A statistical region (a spatial unit with defined maximum parameters regarding the number of dwellings and population) was adopted as the basic spatial unit for determining sub-city districts. Since statistical regions are too small units in terms of the number of population (maximum 2 500), they have been aggregated.

The coefficient of location was a delimitation tool used for aggregating regions, whereas households, for which the main source of maintenance was non-earned sources (retirement pay, disability pension, unemployment benefits, social assistance benefits) were the surveyed entity. The application of the concentration index made it possible to delimit SCDs which were relatively homogeneous in terms of this parameter.

Procedure:

1. The coefficient of location was calculated for each statistical region based on data obtained from the Census 2002. The following variables were used to calculate the coefficient:

• the number of households for which the main source of maintenance was non-earned sources (retirement pay, pensions, benefits) in the statistical region,
• the number of households, for which the main source of maintenance was non-earned sources (retirement pay, pensions, benefits) in the whole city,
• the total number of households in the statistical region,
• the total number of households in the whole city.

2. At the next stage, the statistical regions were aggregated into larger units taking into account:

• an approximate value of the coefficient,
• the location (vicinity) of a spatial unit,
• a variable regarding the total number in the population was additionally introduced, allowing the calculation of the number in the population to control the size of a given unit.