For instance, the choice of the proportional electoral system may ensure an effective participation, even when no exception is introduced to the general electoral system. But obviously when a threshold is introduced, the provision for a lower threshold for the national minorities parties implies special exceptions to the general rules. On the other side, single member electoral districts in areas where territorially concentrated minorities are present, may imply an exception to the general rules on allocation of seats only if the number of electors assigned to the minority electoral districts are not complying with the criteria of the general distribution of voters in the electoral districts provided for by the general rules of electoral law. Reserved seats are a more obvious way of favouring minority representation.