All of David Roodman's Comments + Replies

I dug waaay into this topic when investigating geomagnetic storms. I found it quite interesting and useful. See 

https://www.openphilanthropy.org/research/geomagnetic-storms-using-extreme-value-theory-to-gauge-the-risk

https://www.openphilanthropy.org/research/updating-my-risk-estimate-for-the-geomagnetic-big-one

But am I reading right that that one doesn't push through to a concrete demonstration of impacts on expected values of interventions?

Interesting question! Certainly it is the nonlinearities in the cost-effectiveness analysis that makes uncertainty matter to an expected value maximizer. If we thought that the cost-effectiveness of an intervention was best modeled as the sum of two uncertain variables (a simple example of a linear model), then the expected value of the intervention would be the sum of the expected values of the two variables. Their uncertainty would not matter.

The most serious effort I know of to incorporate uncertainty into the GiveWell cost-effectiveness analysis is thi... (read more)

Good question! I think it brings out a couple of subtleties.

First, in putting forward the "universal" truth that education and earnings go hand-in-hand, I mean that this is a regularly found society-level statistical association. It does not mean that it holds true for every individual and it does not take a position on causality. So I don't mean to imply that if a particular child is made to go to school more this will "universally" cause  the kid to earn more later.

In particular, while I think poorer regencies got more schools and that increased pri... (read more)

I can do both--economics has a long tradition of accepting circulation of "working papers" or "preprints" without jeopardizing publication in journals. In fact, Esther suggested I hold off submitting a comment to the AER until she steps down as editor in a few weeks.

Actually, if clustering was not  as common in 2001 as now, it was not rare. She clustered standard errors in the other two chapters in her thesis. My future colleague Mead Over coauthored a program in 1996 for clustering standard errors in instrumental variables regressions in Stata.

Hi Ozzie. I'm out of my depth here, but what I had in mind was the Uwezo program at one of my "this" links, which I believe was inspired by Pratham in India. I think these organizations originally gained fame for conducting their own surveys of how much (or little) children were actually learning, in an attempt to hold the education system accountable for results.

But that's surely just a small part of a large topic, how a citizenry holds a public bureaucracy more accountable. Specific solutions include "democracy"... You know, so just do that.

I should say ... (read more)

Thanks for the feedback. I can see why that is confusing. You figured it out. I inserted a couple of sentences before the first table to clarify. And I changed "young-old pay gap" to "old-young pay gap" because I think the hyphen reads, at least subliminally, like a minus sign.

Thanks @MHR.

1. Is exactly the right question. My work is just one input to answering it. My coworkers are confronting it more directly, but I think nothing is public at this point. My gut is that the result is broadly representative and that expanding schooling supply alone is often pushing on a string.  It is well documented that in many primary schools in poor countries, kids are learning pitifully little. Dig into the question of why, and it has do with lack of accountability of teachers and school systems for results, which in turn has to do with ... (read more)

Hi Karthik. Without belaboring shades of emphasis, I basically agree with you. But you know, I've just spent thousands of words criticizing someone's work and I want to end positively, within reason.

I agree with much of this. A few responses.

As I see it, there are a couple of different reasons to fit hyperbolic growth models — or, rather, models of form (dY/dt)/Y = aY^b + c — to historical growth data.

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I think the distinction between testing a theory and testing a mathematical model makes sense, but the two are intertwined. A theory will tend naturally to to imply a mathematical model, but perhaps less so the other way around. So I would say Kremer is testing both a theory and and model—not confined to just one side of that di... (read more)

Thank you Ben for this thoughtful and provocative review. As you know I inserted a bunch of comments on the Google doc. I've skimmed the dialog between you and Paul but haven't absorbed all its details. I think I mostly agree with Paul. I'll distill a few thoughts here.

1. The value of outside views

In a previous comment, Ben wrote:

My general feeling towards the evolution of the economy over the past ten thousand years, reading historical analysis, is something like: “Oh wow, this seems really complex and heterogeneous. It’d be very surprising if we could mo