I’ve often been asked what I think about the Ottaviano-Peri finding that there are strong complementarities between comparably skilled immigrants and natives—complementarities that lead them to conclude that immigration raises wages for many natives.
I’ve always been a little skeptical of the Ottaviano-Peri evidence. A couple of years ago, Jeff Grogger, Gordon Hanson, and I worked on a paper that examined the link between immigration and African-American economic status. As a by-product of that work, we explicitly attempted to replicate the Ottaviano-Peri finding--but couldn’t. Since then, we’ve been quite interested in trying to see what explains the discrepancy between our evidence and theirs.
Well, we have finally figured it out. Here’s the abstract to our new paper:
In a recent paper, Ottaviano and Peri (2007a) report evidence that immigrant and native workers are not perfect substitutes within narrowly defined skill groups. The resulting complementarities have important policy implications because immigration may then raise the wage of many native-born workers. We examine the Ottaviano-Peri empirical exercise and show that their finding of imperfect substitution is fragile and depends on the way the sample of working persons is constructed. There is a great deal of heterogeneity in labor market attachment among workers and the finding of imperfect substitution disappears once the analysis adjusts for such heterogeneity. As an example, the finding of immigrant-native complementarity evaporates simply by removing high school students from the data (under the Ottaviano and Peri classification, currently enrolled high school juniors and seniors are included among high school dropouts, which substantially increases the counts of young low-skilled workers ). More generally, we cannot reject the hypothesis that comparably skilled immigrant and native workers are perfect substitutes once the empirical exercise uses standard methods to carefully construct the variables representing factor prices and factor supplies.
English translation: The Ottaviano and Peri data includes currently enrolled high school juniors and seniors. They classify these high school juniors and seniors as part of the "high school dropout" workforce. Their finding of immigrant-native complementarity disappears if the analysis excludes these high school juniors and seniors.
Things that seem too good to be true usually aren’t.
(For the econometric geek who wants to play around with the data and see for himself/herself what is going on: We've created a STATA program archive that allows easy replication of all of the results in our paper. It is available here).