The Null Hypothesis in Education, Restated

By request. I probably should look up earlier statements before writing this, but I hope I am consistent. Consider an education intervention and a set of tests that it must pass. The intervention could be “more spending” or “method X used in the classroom” or “longer school days” or “charter schools” or what have you.

1. It should show a meaningful difference under experimental conditions, meaning that selection bias is eliminated.

2. The difference should persist, rather than fade out. If you show a difference in first grade but by third grade or fifth grade the experimental group is on on the same level as the control group, then there is fade-out.

3. The results should be replicated. One experiment that works one time does not count.

4. The intervention should be scalable. The intervention does not depend on a uniquely gifted teacher.

The Null Hypothesis is that no intervention passes all four tests.

Tyler Cowen on Culture and Economics

He writes,

how do differences of culture — however defined — interact with traditional economic mechanisms involving prices, incomes, and simple comparative statics? Are those competing explanations, namely cultural vs. economic? Ought they to dovetail nicely in some kind of broader explanation? Or might the cultural factors in some manner be “reduced” to questions of more traditional economics? Some combination of the above? Something else altogether? And, from among these and other options, what principles of differentiation rule how “culture” and “economics” will be related in a particular problem?

That to me is the most important unsolved problem in economics and indeed in social science more broadly.

1. I do not think that problems get “solved” in economics the way that they do in physics. We come up with interpretive frameworks, the way that historians do. Some of our frameworks, like supply and demand in microeconomics, seem pretty robust. Others are flimsier and faddish.

2. My current definition of culture is: socially communicated thought patterns and behavioral tendencies.

3. Economic behavior fits within this definition of culture. There is plenty of social communication involved in determining how people conduct themselves in markets.

4. There is tension here, in that a lot of our interpretive frameworks start with very individualistic assumptions. People are presumed to make their own choices, given the opportunities and constraints that they face.

5. The individualistic models get you somewhere when the other cultural factors are held constant. Fix the country and look at narrow slices of time and specific industries, and you have a good chance using ordinary economics. But a lot of interesting questions (why did different countries achieve what McCloskey calls The Great Enrichment at different times? why is southern Italy poorer than northern Italy? why did mortgage securitization balloon and then collapse? why is labor force participation declining?) are affected by cultural factors that differ across time and/or location. That’s when standard economics alone falls short.

What Are Americans Moving Less?

Timothy Taylor writes,

between the 2002-3 and 2015-16 measurements, the share of moves that were 50 miles or less rose from 32.3% of all moves to 42.3% of all moves. The main offsetting decline was in moves of between 200 to 499 miles, which fell from 20.7% of all moves back in 2002-3 to 13.8% in 2015-16.

Those strike me as large changes. Taylor discusses many possible explanations. One story that he does not consider is the possibility that employment opportunities and housing construction have become disconnected. In cities where they might be job opportunities, such as San Francisco, housing is not allowed to be built. In places where housing is allowed to be built, there are not as many job opportunities.

On the Topic of the Day

Joel Kotkin writes,

America is a nation of many economies, but those that produce real, tangible things — food, fiber, energy and manufactured goods — went overwhelmingly for Trump.

On Facebook, I wrote,

I feel sorry for the supporters of both candidates. I think of Mr. Trump’s supporters as people who over the years have grown our food, worked to supply us with fuel, sent their sons to fight in our wars, and yet are in regions that are declining due to forces beyond their control. Mr. Trump got their hopes up, and I doubt that he can deliver.

I think of Mrs. Clinton’s supporters as well intentioned people who are now stunned and worried. Losing an election does not make you wrong or make you a bad person. I hope that it turns out that this election still leaves us free, prosperous, and safe.

Somehow, this seems apropos:

Technical Difficulties

I continue to have problems reaching this blog (which means I have a hard time updating it). Others are also reporting problems.

The best advice I have gotten has been to re-start my router. This has worked a couple of times, including just now. I have no idea why the router wants to stop talking to the site. It is fine with in general, but getting to often fails, and logging into wordpress often fails.

Blogging will be light for a while, as we adjust to being grandparents.

in hospital

I have no idea why WordPress insists on turning us upside down.

DC’s Metro as infrastructure

Popular naratives to describe the problems of the DC metro system:

1. Epitomizes America’s failure to invest enough in infrastructure.

2. Results from unwieldy government structure.

My view:

Metro is an example of over-investment and malinvestment in infrastructure.

Metro’s problem is less one of poor governance than one of lack of economic viability. The demand curve is too far below the cost curve.

What is new is that more of the people who live in DC and are inclined to do without a car are white and affluent rather than black and poor. I do not see why this strengthens the moral case for non-riders to subsidize riders, although I can see how it will strengthen the political ability to advocate for subsidies.

Book Review

Over at, I have written a review of Thomas Leonard’s book on the early progressive economists. My essay is called Dismal Race “scientists.”