Thursday, June 24, 2010

Wednesday, June 23, 2010

Law of One Price Fail

I'm sure it was a signage mistake, but today I was driving down US11 into Lexington, and the Texaco just north of city limits had gas for 2.549 per gallon. Soon afterward I realized I needed something from home and as I was driving the other direction, and the same gas station had gas for 2.599 per gallon. This didn't seem too strange at first - they just changed the price, right? Wrong. On my way back into town, the southbound price was still 2.549. I couldn't help turning back to check - the northbound price was also still 2.599. Probably just an oversight in operation of the manual price sign, but funny to me...

The Hubbub about Teaching Evaluations

There is some interesting debate (Mankiw, Cowen, and Jeff Ely) going on about measuring teacher quality at the postsecondary level. A couple of good sentences from this article, which recently appeared in the Journal of Political Economy (ungated version here).
In primary and secondary education, measures of teacher quality are
often based on contemporaneous student performance on standard-ized
achievement tests. In the postsecondary environment, scores on student
evaluations of professors are typically used to measure teaching
quality.
A lot of us question why this should be the case, and some of us actively doubt the competence of students when it comes to evaluating teacher quality. My own view is that these evaluations are a signal of some things the professor might be doing well and certain other things that the professor might improve, but they do a poor job of measuring how well the instructor did at teaching the actual material. Sometimes they measure little more than popularity (which is not altogether unimportant!). But here are some interesting results:
[O]ur results indicate that professors who excel at promoting contemporaneous student achievement, on average, harm the subsequent performance of their students in more advanced classes.
In other words, students of harder professors for introductory courses (who may struggle and give lower evaluations of that professor) do better in subsequent courses. Higher rank and experience (and thus lower pressured to get good evaluations for tenure) are negatively correlated with current "value-added" in introductory coursework, but positively correlated with value-added in subsequent courses.

Tuesday, June 22, 2010

Subprime Lending and Lobbying

Funny. Lots of "government failure" advocates for explaining the housing bubble point to all sorts of things that the democrats did in the 1970s and before (in addition to the horrible, horrible greed of poor people) for somehow precipitating the sudden rise in subprime loans. Few point to this (note the bill's sponsor), and even fewer likely want to see this (full, but gated, article here).

Monday, June 21, 2010

Some Links, Featuring Tourette's, Dilbert, and a Baseball Mystery

Advantages to Tourette's (British Psychological Society HT: TC @ MR)?
Dilbert, "cheaper" copies, and teaching managers about opportunity cost (Freakonomics).
Why are there so many power-hitting middle infielders these days (Economix)?
A couple of links on "cap and trade" vs. the carbon tax (Economix and Economist)
Libertarianism explained: a review of Jeffrey Miron's "Libertarianism, from A to Z." (Economix). Here is an interesting excerpt:
Professor Miron writes that “antipoverty spending is the most defensible kind of redistribution,” because “the goal of this redistribution – helping the poor – is reasonable and the costs of a well-designed limited antipoverty program (e.g., a negative income tax set on a state-by-state basis) are modest.”
Another interesting quotation on libertarianism (From Raj Pate's "The Value of Nothing"; HT to Atin Basu and Greg Lippiatt):
"There are two novels that can transform a 14 year old kid's life: The Lord of the Rings and Atlas Shurgged. One is a childish daydream that can lead to an emotionally stunted, socially crippled adulthood in which large chunks of the day are spent inventing ways to make real life more like a fantasy novel. The other is a book about orcs."