On Borjas, Data and More Data

I see my craft as an economic historian as a dual mission. The first is to answer historical question by using economic theory (and in the process enliven economic theory through the use of history). The second relates to my obsessive-compulsive nature which can be observed by how much attention and care I give to getting the data right. My co-authors have often observed me “freaking out” over a possible improvement in data quality or be plagued by doubts over whether or not I had gone “one assumption too far” (pun on a bridge too far). Sometimes, I wish more economists would follow my historian-like freakouts over data quality. Why?

Because of this!

In that paper, Michael Clemens (whom I secretly admire – not so secretly now that I have written it on a blog) criticizes the recent paper produced by George Borjas showing the negative effect of immigration on wages for workers without a high school degree. Using the famous Mariel boatlift of 1980, Clemens basically shows that there were pressures on the US Census Bureau at the same time as the boatlift to add more black workers without high school degrees. This previously underrepresented group surged in importance within the survey data. However since that underrepresented group had lower wages than the average of the wider group of workers without high school degrees, there was an composition effect at play that caused wages to fall (in appearance). However, a composition effect is also a bias causing an artificial drop in wages and this drove the results produced by Borjas (and underestimated the conclusion made by David Card in his original paper to which Borjas was replying).

This is cautionary tale about the limits of econometrics. After all, a regression is only as good as the data it uses and suited to the question it seeks to answer. Sometimes, simple Ordinary Least Squares are excellent tools. When the question is broad and/or the data is excellent, an OLS can be a sufficient and necessary condition to a viable answer. However, the narrower the question (i.e. is there an effect of immigration only on unskilled and low-education workers), the better the method has to be. The problem is that the better methods often require better data as well. To obtain the latter, one must know the details of a data source. This is why I am nuts over data accuracy. Even small things matter – like a shift in the representation of blacks in survey data – in these cases. Otherwise, you end up with your results being reversed by very minor changes (see this paper in Journal of Economic Methodology for examples).

This is why I freak out over data. Maybe I can make two suggestions about sharing my freak-outs.

The first is to prefer a skewed ratio of data quality to advanced methods (i.e. simple methods with crazy-data). This reduces the chances of being criticized for relying on weak assumptions. The second is to take a leaf out of the book of the historians. While historians are often averse to advantaged data techniques (I remember a case when I had to explain panel data regressions to historians which ended terribly for me), they are very respectful of data sources. I have seen historians nurture datasets for years before being willing to present them. When published, they generally stand up to scrutiny because of the extensive wealth of details compiled.

That’s it folks.


On immigration, trade, and inequality: why nobody should care (that much)

Recently, I read snippets from George Borjas’s book, We Wanted Workers (I got distracted and reverted to reading Leah Platt Boustan’s Competition in the Promised Land).On its heels came this article by Dani Rodrik in Foreign Policy. Both work make the same case, that free movement of goods and people may imply some negative effects on inequality. Borjas argues that immigration increases inequality while Rodrik argues that low-skilled workers are displaced.

Both arguments are not convincing.

First of all, immigration will always increase inequality in one area. This is by definition. Unless the migrants follow the same distributional pattern as the host population, inequality will increase. If somebody from Cuba enters the United States at the tenth percentile, he increases inequality by swelling the ranks of low earners. If somebody from China enters the United States at the 90th percentile, he increases inequality by swelling the ranks of the high earners. However, from a global perspective (world population), inequality has actually dropped since the migrant has a greater income than in the past. After all, bringing a Haitian to the US may increase US inequality measures but the ten-fold increase in his income (this number comes from my colleague Ben Powell) means that worldwide inequality drops.

To be honest, I know that Borjas is probably aware of this point, but many of those who spin his work don’t get it. Borjas’s argument is little more sophisticated. His claim is that low-skilled workers (high school dropouts) see their wages go down while everybody else (high school graduates and university graduates) gains from immigration. This increases inequality because they are left behind economically. But this is where his argument is alike that of Rodrik and where it misses the target dramatically.

While I could be lazy and simply say that many other scholars place Borjas at the extreme of the spectrum of academics with regards to the effects of immigration on labor markets. Indeed, there are more scholars who find that low-skilled workers also gain from immigration all things being equal. But, I won’t be lazy. Let me assume, for the sake of argument, that the empirical result is valid. If unskilled workers are displaced, why can’t they find new employment elsewhere. If the effects of immigration are so positive for everybody else, it means that everybody else is substantially richer and they can demand more goods. Are there barriers preventing the unskilled from acquiring jobs? The answer is emphatically yes.

The ability to find a new form of employment following changes in the labor market depends on the frictions that exist on the labor market. Some of them are natural. We have to assume search costs (time, energy, some money) to look for a job and get the training for that job. But there are also barriers that create unnecessary frictions. The rise of occupational licencing is one of those (growing) frictions (see here, here and here). We could also point out that product regulations tend to affect the prices of goods that weigh more heavily in the consumption baskets of lower-income workers (here and here) thus pulling the poorest down. We could also point to the fact that states with right to work laws seem to have enjoyed more limited increases in inequality than the states without such laws (here). We could also underline the fact that housing regulations are making it harder for unskilled workers to move to dynamic areas, thus locking them in low-productivity areas (here). And the list could go on for a few more pages, but I think the point is made: there are tons of factors that make displacement a problem. However, those who worry about it when it comes from changes resulting from trade or immigration are concerned with a minor (and positive in the long-run) variable. In a way, Borjas and Rodrik are (rightfully) concerned about the poorest but they fail to identify the problem like if a doctor was concerned with his patient’s loss of sight rather than concentrating on the brain tumor that caused the loss.

Free trade and open borders generate massive benefits. But there are short-term costs as production methods and resources are being reallocated. Many government policies amplify exponentially these costs and delay reallocation. This creates the inequality they bemoan.