A recent and well known paper, Bove and Elia (2017), argues that migrants' diversity, as captured by the indexes of both fractionalization and polarization, exerts a positive effect on GDP growth. In fact, by using the same dataset and methodology, we show that the impact of diversity cannot be distinguished from that of migration itself due to the very high correlation among the corresponding variables. Also, if one disentangles migration from diversity, following Alesina et al. (2016), only migration maintains a positive impact on growth while diversity, as captured by fractionalization, turns out to be weakly and positively associated with growth, but limitedly to the 1980-2010 time span. Polarization, on the other hand, does not seem to exert any effect on growth. The question as to whether diversity is more or less beneficial in terms of economic growth remains therefore an intriguing one, and calls for more theoretical and empirical analyses, possibly based on less (geographically) aggregated data.
