Too much of a good thing?

My attention has been drawn (thanks Paul) to an article which describes how one might find the optimal number of members of parliament in a representative democracy.

In a nutshell, a parliament with too few representatives is not “democratic” enough, possibly leading to an unstable political system, in which various undesirable forms of political expression, including of course violent ones, will develop. In contrast, too many representatives entail substantial direct and indirect social costs, they tend to vote too many acts, interfere too much with the operation of markets, increase red tape and create many opportunities for influence, rent-seeking activities and corruption.

In their paper the authors derive a formula in which the optimal number of representatives is approximately proportional to the square root of the population of the country.

They test their formula against the data and find that Israel, New Zealand, the Netherlands and the USA have far too few representatives. I’m not sure how this correlates with their predictions about the instability of under-represented democracies: all four countries are very stable, non-violent democracies as far as I’m aware. I don’t have access to the CEPR paper but I’d be curious as to whether they address this issue. Their model makes some predictions which are easily falsifiable and I’d like to know how it stacks up against the evidence.

  • Richard

    Having looked at the article but not the paper, the assertion that too few leads to problems seems to be nonsense given the countries with too few are amongst the more stable of the worlds democracies. http://www.economist.com/markets/rankings/displaystory.cfm?story_id=8908438

    Also that it appears to leave out state govt, especially in the US or Oz, seems to make the study generally questionable given control state govts on red-tape. I’d also not that Italy, France and Spain have much in common in terms of polictical culture that would influence the behaviour of their legislators perhaps more than the number of legislators.

    And why you popped my blog on the left? It gave my mates a laugh at least 😉

  • Matt Nolan

    I have no idea why we put you on the left. My excuse is that the left wing and right wing boxes are right next to each other, and I just clicked the wrong one 😉

  • I understood the standard “rule” was even simpler – the legislature should approximate the cube root of the population.

  • rauparaha

    In the article they say that the relationship they derive is a square-root, but the observed relationship is more like the population raised to a power of 0.4. So the cube root rule may be empirically a little closer to reality but not optimality according to the paper.

  • Richard

    Hoo-ray, I’m right-wing again!