Talk:Duverger's law
Is it really necessary to link to two-party system twice in this article? This has been added and reverted quite a few times. -- RobLa 03:41, 1 Mar 2004 (UTC)
One thing I've always wondered is how Duverger's law applies in the case of other single-winner methods. Did Duverger just make a dichotomy between first-past-the-post and proportional representation? -- Dissident 19:04, 1 Mar 2004 (UTC)
"There are numerous counterexamples: Malta has a single transferable vote system and what seems to be stable two-party politics;"
This is a logical fallacy. "...first-past-the-post election system naturally leads to a two-party system..." is not the same as "two party system requires first-past-the-post". The fact that Malta has two parties doesn't contradict the 'law', at least as it is explained in the current article.
Unfortunately, I don't know whether the mistake is in the statement of the principal of the description of the Maltese political system, so I'll have to leave this for someone else to fix. --Rory ☺ 14:20, Mar 22, 2004 (UTC)
- I agree, and further assert that it isn't merely a logical fallacy, but in fact, an inappropriate example. There are many (including myself) that have come to believe that single transferable vote also leads to a two-party system. -- RobLa 08:13, 23 Mar 2004 (UTC)
- I won't press the point in the article - moving Malta down works for me - but I read Duverger's law as saying that first-past-the-post is more likely to produce two-party results than other voting systems are; it doesn't say FPTP inevitably leads to two parties. So there are two types of exceptions (if you can have exceptions to a principle): FPTP with several parties, and two party systems with a more proportional voting system. Incidentally, Australia only uses STV for the Senate, but AV for the more important House of Representatives. --Henrygb 23:06, 23 Mar 2004 (UTC)
Scotland is not an example, in any respect, to a refutation of Duverger's Law. The law states that FPTP leads to a two party system. Scotland's Parliament is eight years old. The next example is the United Kingdom, which does not use FPTP, but mixed representation. Canada has a very regulated, non-partisan system.
It looks like every counter example is bogus. India, for example, has regional parties, but is there any constituency with more than two main parties? If not, Duverger's Law would appear to apply.
There also ought to be an explanation why Duverger's Law works. Namely, strategic voting in a unidimensional sytem under FPTP results in a simple, rational aggregate "hedging" strategy.
JoshNarins 20:17, 1 November 2005 (UTC)
- Duverger's Law is explained partially by strategic voting but also by the incentive for parties to improve their changes of winning a seat through merging or coalitions (and conversely, by providing a disincentive for an internal faction to split off). See, e.g., "Structure and Behaviour: Extending Duverger's Law to the Japanese Case" by Steven R. Reed [British Journal of Political Science, Vol. 20, No. 3. (Jul., 1990), pp. 335-356.] This article also generalizes Duverger's law to multimember districts: for n seats there will be n+1 candidates at equilibrium. - ChrisKennedy(talk) 03:30, 3 December 2006 (UTC)
Any anglo-american attempt on analyzing, describing FPTP, single-seat-district, winner-takes-all, two-party-systems seems to have to wait until UK finally does their promised Jenkins_Committee reform of their domestic election system.
just check out citizens assembly, the struggles in Canada.
Note, if an election-system has two elected institutions, for example "house" and "senate", "lower" and "upper" parliament, the result becomes more complex. Adding a system for electing a president makes it more complicated. However, the basic mechanism is "at the local level", single-seat, FPTP, winner-takes-all mechanisms.
In Canada I think that the regional politics, which are mentioned in passing in this article, have a much larger influence. At the moment each political party has a regional bias, most especially the Bloc Quebecois which is only in Quebec, but even the NDP, Liberals, and Conservative parties have regional biases. I suspect this is true in many other countries that have strongly differentiated regional cultures. Sbwoodside 19:50, 12 March 2006 (UTC)
Finland is not a counterexample, they have a proportional representation system. http://en.wikipedia.org/wiki/Parliament_of_Finland#Parliamentary_elections
Graph
I had an idea for a visualization of this, showing the proportion of votes that went to each party for each US presidential election, and showing how two parties take the majority of the vote, and those two parties only change occasionally, as described in the article about the Whig party. (Inspired by these graphs, though an implementation of this would be percentage-based, and so constant-width.) But the actual data is a little more complex, with multiple people running for the same party, the original elections with no parties, etc. Any ideas? — Omegatron 01:43, 2 September 2007 (UTC)
- In my opinion stacked bar graphs make comparisons across years difficult. The linked graphic makes it hard to tell how Republican votes compare to Democratic votes because the independent candidates are always listed on the top. I would prefer a non-stacked bar graph with parties listed next to one another and grouped by election. - ChrisKennedy(talk) 02:40, 2 September 2007 (UTC)
- Additional chart suggestions (based on Edward Tufte's writings): remove the bar border, remove the two decimal places from the y-axis labels, change the y-axis interval from 10% to 20%, remove the ticks from the x-and y-axis labels, make the axis lines a light gray (50% or so) to reduce their prominence (dashed might be good too), and remove the border from the legend. The color difference between Libertarian and Green party is also negligible - I'd make Libertarian orange so that it stands out more. - ChrisKennedy(talk) 02:47, 2 September 2007 (UTC)