Wednesday, November 25, 2009

A Coherent Kristof?

Kristof actually presents a pretty coherent summary of the positions of the major players in the economics of international development.

Sunday, November 22, 2009

Please, No Rubber

Quite unexpectedly, "Please, no rubber" is a major part of my vocabulary here. No no, it doesn't mean that. A "rubber" in Ghanaian english is a plastic bag in American english (I still feel awkward saying it, though). And are rubbers everywhere in Ghana. Any street food comes packed in two, or even three, small black "rubbers." At the provisions store near my house they pack every can/bottle individually in its own rubber. I always feel a twinge of guilt throwing away the seven rubbers I got from buying three items, but it's often easier to just take them than it is to explain that I can carry a pineapple without it being double-bagged.

It's obvious where the rubbers end up: streets, gutters, vacant lots, and trash heaps are filled with them. But until the other day, I had no idea where they come from. What does it take to make a plastic bag? Are there giant cargo ships full of plastic bags arriving daily from China? Who profits off a rubber?

And then I discovered the Ghanaian rubber-making industry.

Meet Thomas, the rubber-maker. Using his feet, he can lower an arm that has a hot wire and a blade running across it. He stretches the tubular plastic roll out to proper rubber-size and lowers the arm down to seal the bottom of one bag with the wire and cut open the top of the next with the blade. Stretch, lower, stretch, lower, Thomas is a one man rubber-making factory.

"Please, no rubber" will be a little harder to say now that I know about Thomas and domestic rubber-making industry.

Saturday, November 21, 2009

Some Congratulations Are Due...

Four out of the five people who read this blog had major accomplishments this week, so I thought I'd highlight them here:

First, congratulations to Dad, who completed his 50th year yesterday.

Next, congratulations to Mom for her successful rotator cuff surgery on Thursday.

Congratulations are also due to Girlfriend, for giving notice at her job, and deciding to move to Ghana. (OK, I'm still working on the second part, but it will come...)

Finally, congratulations to Brother, for purchasing a one way ticket to Chile on Wednesday.

Tuesday, November 17, 2009

Belichick Update

Greg Mankiw is also on Belichick's side, and links to an interesting story on Belichick's reliance on data.

I read a little bit more of the paper but am still not convinced that Romer's analysis translates to the Pats situation. Using data from 3rd downs and the 1st quarter just doesn't translate to 4th and 2 with 2 minutes to go. I don't think I can write anymore about it without getting some thicker nerd-glasses, but two quick points: At the end of a tight game like that, the returns to getting exactly two yards are exactly equal to the returns to getting 20 yards -- you win the game in either case -- so the defense is going to sit right on the first down line and not let you past. If it's the first quarter and a third down, the returns to 20 yards are much greater than the returns to 2, so the defense has to respect the deep ball and play off the line, increasing your chance to make a 2 yard gain.

The second point is that points come in important, discrete bunches (3 points for a field goal and 7 for a TD). This may have been addressed in the paper and I just didn't read it closely, but you would have to do the analysis looking only at the probability of the opposing team scoring a touchdown to replicate the Pats situation. If you are just averaging the opposing points scored the field goals would raise the average but with a 6 point lead the Pats could care less if the Colts kicked a field goal at the end of their drive.

Monday, November 16, 2009

Is Bill Belichick Great?

Unfortunately, I missed the latest Pats game. Well, to be honest, I've missed every Pats game... but that's neither here nor there (if we're being specific, it's there and not here...) However I do hear that Bill Belichick made a questionable call on 4th and 2 in his own territory. Pop economist Steven Levitt loved the call, saying that it was statistically the correct thing to do.

But was it? The claim is based on a paper by respected economist David Romer, which I haven't read, but assume deals with correlations between punting versus going for it and points scored. That is, non-experimental data: I don't think that anyone is actually randomly assigning 4th downs to punt on and 4th downs to go for it (following Romer's rules for what yardages are appropriate). This means there's no accounting for a coaches intuition, his observations about the relative levels of fatigue or any other hunch that can't be captured by statistics.

Glancing at the paper, Romer also used data only from the 1st quarter and used the expected yardage gain from 3rd downs as the expected gain from 4th downs (because there are too few actual 'go for it' 4th downs for analysis). So even if the paper was correct about punting to be a bad option, punting might only be a bad option in the 1st quarter and if the opposing defense plays the same way it would as if it were 3rd down (unlikely).

The data, then, might not be so clearly on Belichick's side after all. I wouldn't be surprised at all if the Pats had a resident statistician who extended Romer's analysis to 4th quarters and 4th downs, but there is still no getting around the fact that coaches' unobservable impressions can't be accounted for in the data but could still be important.

So what were your impressions? Did the Pats look like they were going to succeed or did it look like a bad idea from the minute they walked on the field?

Wednesday, November 11, 2009

An Online Ghanaian Yellow Pages?

One thing that we have been entirely unsuccessful at in our office is finding a place that will deliver lunch. The kitchen/wait staff at the restaurants around are never in any particular hurry and lunch can actually be a substantial time drain. Yesterday was a fairly busy day, so when a colleague suggested that we try to find the number for our favorite Lebanese restaurant online, I was down but very skeptical that we would find anything.

I was amazed when she sent me this link and asked if I could call. What could this link be? An online Ghanaian yellow pages? No, it looks like it has reviews and contact information! Amazing! But wait! Where is the contact information?!

I read it over three or four times without seeing a phone number before finally asking the colleague how she expected me to be able to call... Her response was brilliant: It's on the sign board in the picture!


(Unfortunately, they didn't answer and we had to go and wait anyway...)

Monday, November 9, 2009

On the IPA Blog

I wrote another post for the IPA blog, which you can read here. It may not show up on the home page unless you hit refresh, for some reason.

It also occurs to me that I may not have linked to my previous post on the IPA blog back in September. It is here.

Friday, November 6, 2009

The Consequences of Sprawl

Via Greg Mankiw's blog, Ed Glaeser has an op-ed in the Boston Globe arguing against the home buyer's tax credit on the grounds that it encourages suburban sprawl and therefore all of the negative environmental consequences of sprawl. I've been in-tune with the green urbanism thinking for a while now, but drifted away recently because it doesn't seem to be going anywhere and if people prefer living in the suburbs, who am I to say they should move back to the cities?

It's great to see such a well-respected economist getting behind the idea that we should limit suburbanization subsidies. My declining interest in urban planning was accompanied by an ascendant interest in economics; Glaeser's article is a nice reminder that the two are not so separate after all.

Thursday, November 5, 2009


Sorry for being MIA on the blog recently. I have a few new posts in the works, but in the meantime, here's another amazing graph:
ht marginal revolution.