Brian Perez

Blog 7

                The electoral system in Chile, consisting of its district magnitude, formula, thresholds, and party-list system, is unique among the countries of the world. Chile is divided into 60 constituencies, each with two congressional seats for each of the two houses of legislature, the Chamber of Deputies and the Senate ("Inter-Parliamentary Union"). Therefore, the district magnitude for each constituency is two. The formula for how seats are allocated is based on a majority. If the majority party wins over two thirds of the votes in a district, it is entitled to both seats. If it wins less than two thirds, it is still entitled to one and the second place party takes the other seat. Chile is the only country in the world to practice this kind of binomial system. A closed non-preferential party-list majority system is in place, meaning a list of candidates for each party is decided on only by the leaders of the party. Low-level party members have no say in the decision. There is a 5% threshold requirement for parties to continue to exist, leading to the integration or collapse of many of the small parties in the country (Navia, and Sandoval).

                Through use of a formula, it can be derived that 2 is the best number of political parties in Chile, with perhaps an additional third party. One formula for determining the effective number of parties is N=1/Σ(), or the number of effective parties is equal to the inverse of the sum of the proportions of votes each party received squared (Navia, and Sandoval).

Party	Number of Votes	Seats	Percentage of Votes	Proportion	Proportion squared
Concertación and Juntos Podemos for More Democracy	2,934,378	57	44.35%	.44	.19
Coalition for Change	2,874,674	58	43.45%	.43	.18
New Majority for Chile	302,627	0	4.57%	.05	.003
Clean Chile Vote Happy	356,798	3	5.39%	.05	.003
Independents	147,379	2	2.23%	.02	.0004
Total	6,615,856	120	100%		.3764

In the table, which describes the outcome of the 2009 congressional election, the five coalitions in Chile are listed with the numbers of votes each received ("Wikipedia"). That number is divided by the total number of votes to find the proportion of votes each party received. These proportions are squared, then added together to get .3764. The inverse of this number is 2.7. Although it is impossible to have seven tenths of a party, the decimal is probably indicating that two parties are not quite enough to represent the entire population. The two major parties represent 87 percent of votes. This is a sizable majority, but perhaps a third party is necessary for optimal efficiency.

                Duverger’s Law states that the effective number of parties in a country can be determined by assessing the electoral system in a country. Chile’s electoral system verifies this claim. It is assumed that a SMDP system, or single-member district plurality, results in a two-party system. While Chile has more of a multi-member district plurality, it is closer to the SMDP system than to a strict proportionality representation system. In PR, seats in congress are granted to each party based on the proportion of votes each party receives. Chile’s unique binomial system results in the two main coalitions taking a huge majority of congressional seats. All but 5 of the seats in the Chamber were won by these two major parties. Indeed, the electoral system of a country does determine the number of effective parties.

Works Cited

"Chile Chamber of Deputies." Inter-Parliamentary Union. N.p.. Web. 1 Nov 2012. 

"Chilean parliamentary election, 2009." Wikipedia. N.p.. Web. 1 Nov 2012.  

Navia, Patricio, and Jose Sandoval. "Binomial Electoral Law and Multi-Party System: The Chilean Contradiction." . N.p.. Web. 1 Nov 2012.