Saturday, September 02, 2006

Probability of razor-thin national election results

Is Mexico going the way of Venezuela, with political violence leading to a hostile government next door?

BBC NEWS | Americas | Mexico deputies stop Fox speech
The original count saw Felipe Calderon - of the National Action Party (PAN) - win just over half a percentage point more support than Mr Lopez Obrador, of the Party of the Democratic Revolution (PRD).
I am highly suspicious of razor-thin national electoral results. I'm no sadistician, and probability gave me a headache in college, but I can't shake the sense that razor-thin national election results are very low-probability events with chicanery the most likely explanation.

It's easy for me to sympathize with a Mexican citizen who voted for Lopez Obrador as he heads out to raise hell at the demonstration.

If there is a good explanation for razor-thin national election results I have not found it. The closest I've found had to do with the likelihood of razor-thin results occurring in a small number of political subdivisions of a larger electorate in which a close election is forecast, but that's not the same thing.

Do razor-thin national election results indicate a high likelihood of chicanery? Is there a better electoral system?

So far I think the answer to both questions is Yes. I'm not particularly hopeful though.


jj mollo said...

This is not a fluke. Razor thin margins are, I believe, a direct result of improvements in survey statistics. Both sides are essentially negotiating with the electorate until the last moment. They know exactly where they are at any moment, they know what they need, and they know what they are willing to trade for it.

Steve said...

Well, that sounds plausible. I'd certainly prefer to believe your surveying explanation over my thoughts about chicanery.

I see there are some promising hits googling "election theory". I'll do a little scanning and see if anything turns up.

jj mollo said...

Razor thin elections have the unfortunate side-effect of increasing the incentive for chicanery. One advantage of the Electoral College system used for presidential elections is to limit the chicanery to just a few swing states.

Another problem is the reluctance people have to put elections behind them when they're so close. IMO, Al Gore showed that he was a Great American simply by letting it go. Obrador is apparently not a Great Mexican. I think the phrase is "sore loser", but I suspect that the motive is actually darker than that. Mexico might need a revolution, but it would be nice if it were a peaceful democratic revolution.