Blog 7:
Duverger’s
Law states that the effective number of parties in a function of the electoral rules.
According to Duverger’s Law the SMPD, or single member district plurality,
rules will produce a two party system. To put this statement to the test we
will be considering the electoral system of the United Kingdom. We will be
focusing on the results of the election of the House of Commons.
The
United Kingdom has a fairly unique set of electoral rules. First of all, the UK
has a “fire past the post” or plurality method to determine who wins. Meaning that
whichever candidate gets the most votes, regardless of what percent they receive,
wins the election. The district magnitude for the UK is one, which makes sense
since they are a single member district plurality system. Another couple of key
aspects in defining the system in the UK are their list structure, and
threshold. There is no threshold for the parties in the UK, so even if a party receives
no votes and no seats in parliament it can still exist as a political party.
And the list structure is a closed and non-preferential structure. This type of
structure allows each political party to choose their own candidates for each district.
Considering these electoral system characteristics and according to Duverger’s
Law the results of the United Kingdom’s parliamentary elections should favor
two political parties over all of the rest.
In
the House of Commons 2005 elections there were 645 seats up for election.
Leading the results the Labour Party won 355 of the total seats, followed by
the Conservative Party with 198 seats, then the Liberal Democrats who won 62
seats, and after that there are nine other parties that each won 9seats or less.
Although it is seemingly obvious that there are only two major parties with a third
party that is slightly less competitive, we will now apply a formula to
determine the effective number of parties, the formula is: (Effective
number of Parties) = 1/∑p2 . If we plug in
the percentages of seats that each party won in the election we get the result
of effective number of parties = 2.45. These results agree with the Law given
by Duverger.
By
examining the electoral system of the United Kingdom we can see that although
Duverger’s Law is not perfectly accurate, because the UK had 2.45 effective
parties rather than 2, it is somewhat accurate. And the results of the 2005
House of Commons elections helps to fortify his Law.
Works
Cited:
“United
Kingdom House of Commons: Electoral System.” Inter-Parliamentary Union.
http://www.ipu.org/parline
“Closed List”
Wikipedia http://en.wikipedia.org/wiki/Closed_list
“House of Commons
of the United Kingdom” Wikipedia http://en.wikipedia.org/wiki/House_of_Commons_of_the_United_Kingdom#Procedure
I did the UK as well using the 2010 election data, and came to the same conclusion! Its interesting though because the party efficiency number is actually higher in 2010
ReplyDeleteIt is interesting the UK has a plurality system like the US but they also have a list where the political parties chose the candidates for each district. I came to associate list structure with proportional representation but perhaps that is not always the case.
ReplyDelete