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‘Metrics Monday: Proxy Variables

It often happens in the course of doing empirical work that we wish study the relationship between some variable of interest D and some outcome Y, but that we don’t have access to a good measure of D. Rather, what we have instead is a proxy for D, which Wikipedia defines as

a variable that is not in itself directly relevant, but that serves in place of an unobservable or immeasurable variable. In order for a variable to be a good proxy, it must have a close correlation, not necessarily linear or positive, with the variable of interest.

For example, we may observe a dummy variable for whether one has started a business as a proxy for entrepreneurial ability. Or we may observe one’s IQ as a proxy for intellectual ability. Or we may observe the frequency of elections as a proxy for democracy. The possibilities here are endless.

For the sake of argument, then let’s denote our proxy variable–what we actually observe in lieu of D–as D*, so that Continue reading

The Books that Have Shaped My Thinking: Econometrics

This post is part of a continuing series on The Books that Have Shaped My Thinking.

It’s the summer, so I have time to read, both for work and for pleasure, and I have time to read books instead of just journal articles and blog posts. This made me realize that while a lot of my thinking has been shaped by things that I have read in journal articles (economics is an article-based field) and in blog posts (there is no better means of spreading important ideas quickly), a large part of my thinking has been shaped by books, which often contain more exciting ideas than journal articles–because they face less strict of a review process, books can be more daring in their claims, and thus have more chances of causing you to change how you view the world.

So I decided to write this series of posts on books that shaped my thinking. I talked about development books three weeks ago; I talked about food and agriculture books two weeks ago; and I talked about economic theory books last week; this week I will talk about econometrics. Some recommendations are very general; others are eminently personal. I just hope you can find one or two that will also shape your own thinking. I’m sure I am forgetting a lot of important books I have read and which have also shaped my thinking, but I made this list by taking quick look at the bookshelves in my office. Conversely, some of the books in this list also appeared in my previous post on The Books that Have Shaped My Thinking. Continue reading

Top 5 Agricultural Economics Journals, As Per the New Impact Factors–2015 Edition

From the ISI Web of Knowledge Journal Citations Report, here is the new top 5 of agricultural economics journals:

  1. Food Policy 1.799
  2. Food Security 1.495
  3. American Journal of Agricultural Economics 1.327
  4. Journal of Agricultural Economics 1.278
  5. European Review of Agricultural Economics 1.271

The number to the right of each journal name is the journal’s impact factor, which has been calculated on the basis of calendar year 2014 citation numbers.

This has not been a good year for agricultural economics journals–both Food Policy, which I edit, and the American Journal of Agricultural Economics, at which I serve as associate editor, have seen their impact factor go down. But that seems to be true of a lot of journals. The Journal of Development Economics, for example, has a new impact factor of 1.798. If I recall correctly, it used to be well above 2. Moreover, a few journals that I believe to be very good surprisingly did not make the top 5.

But that is only one top 5. Bear in mind that the rank ordering might differ significantly depending on what other indicators of quality you look at, or whether you consider reputation. In agricultural and applied economics departments, for example, many people still consider the AJAE as the no-contest top journal in the field, no matter what impact factors say.