From Statistics Explained
An observation unit, sometimes also called statistical unit, is the entity on which information is received and statistics are compiled in the process of collecting statistical data.
An observation is the value, at a particular period, of a particular variable, such as the individual price of an item at a given outlet.
Observation units vary according to the specific survey or data collection:
- for statistical data collected on persons the observation unit is usually one individual or a household;
- in economic or social surveys collecting data on enterprises, the observation unit can be:
- an enterprise: a legally recognised organisational unit carrying out one or more activities at one or more locations; enterprises are classified into sectors (by NACE) according to their main activity;
- a local unit: an enterprise or part of an enterprise (factory, warehouse, office) situated in one geographically identified place; local units are classified into sectors (by NACE) according to their main activity;
- a kind-of-activity unit, abbreviated as KAU: an enterprise or part of an enterprise which in its entirety can be classified within one activity sector (by NACE);
- a local kind-of-activity unit, a combination of the previous two: an enterprise or part of an enterprise situated in one geographically identified place which in its entirety can be classified within one activity sector (by NACE);
- One enterprise can have a number of local units and/or kind-of-activity units. One local unit can comprise several local kind-of-activity units. It is possible that the main activity of a local unit is not the same as the one of the enterprise to which it belongs.