Locality
An urban settlement is a cluster of dwellings with at least 200 inhabitants. The delimitation is based on the population information of the previous year. Urban settlements are defined and delimited in co-operation with the Finnish Environment Institute using geographic information methods that utilise the building and population data of Statistics Finland's 250 m x 250 m grid data. The population size of grids containing buildings and their neighbouring grids, as well as the number of buildings and their floor area, are reviewed in the definition. From the uniform clusters of dwellings generated in the defining stage, the ones with at least 200 inhabitants are selected.

Sub-area (of municipality)
Municipal sub-areas are formed of operationally functional wholes defined by the municipality itself, which are the basis of the municipality's regional planning and monitoring. Statistics Finland is responsible for digitising new sub-area boundaries and for maintaining name files. Municipalities have the opportunity to check their sub-area division once a year.
The division into sub-areas is a hierarchical three-level classification which has a 1-digit major area level, a 2-digit statistical area level and a 3-digit small area level. Sub-areas are numbered consecutively using these three hierarchical levels. The 6-digit sub-area code is bound to the 3-digit municipality code, so the sub-area code consists of a total of nine characters.

Persons working in the area
Persons working in the area refers to all persons who go to work in the area concerned irrespective of their place of residence. Persons working in the area form the so-called employed day population, the size of which can be regarded as a measure of the number of workplaces in the area.

Workplace
The number of persons working in a certain area can be used to describe the number of jobs in that area. Each employed person is thus thought to represent one job. This means that even part-time work is included in the workplace statistics. If, for example, the work of someone on maternity leave is done by a substitute, two workplaces may be registered. Employment may also be of temporary or short-term in nature.
In the register-based censuses and in the employment statistics no distinction has been made between work done at fixed workplaces and work of mobile nature. Instead, all persons are allocated to some establishment regardless of the nature of the work. If exact data on the location of a workplace are lacking, persons are placed in the municipality where they live. For the majority of self-employed the location of their workplace is the same as the municipality where they live.
Workplace numbers can be distorted by flaws in data sources. For example, where detailed information on the workplace of a person employed in a company with several establishments is missing, the person's workplace is fixed to that person's place of residence, or persons may accumulate in a company's main establishment.