Principles
Principle 1: Population thresholds
The NUTS regulation defines minimum and maximum population thresholds for the size of the NUTS regions:
| Level | Minimum | Maximum |
|---|---|---|
| NUTS 1 | 3 000 000 | 7 000 000 |
| NUTS 2 | 800 000 | 3 000 000 |
| NUTS 3 | 150 000 | 800 000 |
For administrative levels of NUTS, it is sufficient if the average size of the corresponding regions lies within the thresholds; in case of non-administrative levels, each individual region should do so. Exceptions exist however in case of geographical, socio-economic, historical, cultural or environmental circumstances.
Despite the aim of ensuring that regions of comparable size all appear at the same NUTS level, each level still contains regions which differ greatly in terms of population.
Principle 2: NUTS favours administrative divisions
For practical reasons the NUTS classification generally mirrors the territorial administrative division of the Member States. This supports the availability of data and the implementation capacity of policy.
Principle 3: Regular and extraordinary amendments
The NUTS classification can be amended, but generally not more frequently than every three years. The amendments are usually based on changes of the territorial structure in one or more Member States.
In case of a substantial reorganisation of the administrative structure of a Member State, amendments to the NUTS may be adopted at intervals of less than 3 years. This has only happened once so far, in 2014 for Portugal.