Territorial constituencies may be broken down into two types:
- Single-member constituencies (one seat in contention per constituency) are the most
widespread today, in particular in the common-law countries. It is possible to make use of such constituencies for elections based on the plurality/majority principle. In contrast, theyare inconceivable for elections based on pure proportional representation.
- Multi-member constituencies (several seats in contention per constituency) are compatible both with plurality/majority systems and proportional representation. As far as plurality/majority voting is concerned, they are used in practice in Europe virtually only for local elections. Outside continental Europe, multi-member constituencies are frequently used for the election of national parliaments.