Nathan Explains Science on Santa Fe Radio Cafe

Sadly, my real job has kept me from doing my real avocation, blogging, and it's especially unfortunate this week since the Republican National Convention is in full swing just in time for hurricane season.

But fear not!

The lovely and talented Mary-Charlotte over at Santa Fe Radio Cafe interviewed me recently on matters political, and you can listen here:

http://www.santaferadiocafe.org/podcasts/?p=2961

People Are Ignorant. Big Deal...Right?

In my previous three posts, I wrote about the fact that people generally don't know much about politics, though there is variance, and I wrote about why people know what they know. Basically, learning about politics takes effort, so people only know the things that are the easiest to learn about, which isn't much.

Okay, so people don't know much about politics, and we have some idea why. Today and next time, I'll look at whether it actually matters. In particular, I'll look at whether individuals and societies can make good decisions in spite of their ignorance. Roughly, there are three arguments:

What "The People" "Want", Part Three: Voting Rules Gone Bad

Last time, I introduced Arrow's Theorem, which states, essentially, that we can't have our voting cake and eat it too. I also showed how plurality rule fails to give us one thing we’d like, transitivity.

Today I want look at the other classic problem: the Borda count and independence of irrelevant alternatives. First, let's review a little bit.

Fielding Reader Questions: The Strength of Voter Preference

Reader F. Tyler asks the following (slightly edited) question regarding the Borda count, a voting method in which people rank alternatives, higher-ranked alternatives get fewer points, and the option with the fewest points wins, just like golf (see this post and its follow-up on basic problems with voting):

What "The People" "Want", Part Two: It Gets Worse.

Last time I talked about what the people want, there were two main points.

First, there are always more than two options. The point of this is that if even in seemingly two-party systems such as that here in the US, there are so-called third parties, and the presence of third-party candidates is sometimes consequential. The big scary example is Allende in Chile in the 1970s; the less scary but more proximate example (for US readers) is Perot in the 1992 US presidential election.

Second, once there are more than two options, what the people "want" is hard to define. Using the Borda count and plurality rule voting methods, I showed how society's first choice depends on the manner in which people decide.

In the academic literature on "social choice," as it's called, the issue is one of preference aggregation and whether it's possible to aggregate preferences in a rational, fair way.

Today, I'll start with a statement of Arrow's Theorem, which answers that question with a resounding "No, it's not possible. Sorry." I'll follow with some intuition, and in future posts I'll flesh out the ideas.

What "The People" "Want", Part One: It Depends

Now that the election is fading from your memories—and I assure you it is—I thought I’d kick off what I hope will be a series of semi-regular posts on how elections really work.