Public Choice lesson of the day

Most people having had a course in microeconomics know about Arrow and some of the problems relating to preference aggregation. Likewise most of them unfortunately probably forget about these things quite soon afterwards, thinking that these theoretical problems are just that – theoretical.

Now there’s some evidence to the contrary. Well, actually the first edition of the paper was published in 2001, so maybe ‘now’ is a bad word to use, but anyway I’ve never seen it before so it’s news to me. From Peter Kurrild-Klitgaards paper presented at The Annual Meeting of the European Public Choice Society: Voting paradoxes under proportional representation: Evidence from eight Danish elections:

The present analysis [...] suggests that some of the social choice paradoxes potentially occurring in proportional election systems actually do occur in reality. Specifically, one social choice paradox is present in virtually all elections using list-systems with proportional representation, albeit to different extents, namely the More-Preferred-Less-Seats Paradox, while two other paradoxes, the Condorcet-Winner-Turns-Loser Paradox and the Condorcet-Loser-Turns-Winner Paradox, seem to occur occasionally.

What does the existence of these paradoxes mean, I hear you ask. Well:

More generally the presence of this particular paradox would seem to contradict a premise underlying much of contemporary democratic theory, namely that if more people prefer one party than another, then it would be wrong for the latter party to receive more seats. It would in particular seem contrary to the views and justifications usually offered in favour of proportional representation, namely that this somehow is more in line with “what the people want”. Proportional representation obviously tends to add pluralism to a party system compared to, e.g., the first-past-the-post system, but it also seem not only to do so by benefiting some parties at the cost of others (which is inevitable) but also to do so in a way that seems intuitively in direct opposition to the majority principle underlying the democratic idea.

[...]

…apparently, it is quite often the case that the preference of a majority of the voters is quite different from what the seat allocations are under proportional representation. This is an insight which should make democrats careful about how they emphasize the values of the democratic process and its outcomes – and be more interested in the consequenses of alternative electoral arrangements.

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I have only looked at a few of the papers from the conference, but it looks like there’s a lot of interesting stuff there. Do take a look if you have the time.