A single-member constituency is an electoral district that returns one officeholder to a body with multiple members such as a legislature. 

Functional or occupational representation is a protest against the system of territorial or geographical representation. In modem States the usual basis of representation is territorial.

Disdvantages:

Advantages:

i. The system of representation based upon classes, professions, occupations, or other groupings of society is not of recent origin. Mirabeau, at the time of the French Revolution, declared that a Legislative Assembly ought to be a mirror of all the interests of society.

ii. The system of functional representation is commonly known as the Soviet system. The geographical or territorial system of representation was replaced in Soviet Russia by a system based on the vocational principle, i.e., workers, farmers, professional men and other classes choose their own representatives without regard to territorial areas.

iii. There are two divergent groups who advocate occupational representation from different motives. The Communists support it, because it centres the voter’s attention upon his work relationships and forces him to think in proletarian terms. The non- Communists, on the other hand, advocate it because of their disgust with the present system of electing legislators from single-member constituencies.

The two methods are : 
i. Direct Elections - Direct election refers to the method of choosing political officeholders in which the voters directly cast ballots for the concerned person or the party whom they wish to see elected. The electoral Elections system used generally chooses the winning party or winner of direct election depending on the majority of votes.

ii. Indirect Elections - Indirect election refers to the method of election in which voters in an election do not choose candidates for an office but they elect people who will then make the ultimate choice. In other words, people do not cast their votes directly in this method. Instead, they put the decision in the hands of others.

The bases: 
i. Historical - In most of the societies, the emergence of political parties has been the result of the evolution of their political systems from monarchical to democratic. 
ii. Socio - Economic - Economic interests and conflict of economic interests have been a popular and quite realistic basis for the formation of political parties.