In a previous post I showed countries 'sending' migrants for legal work-related reasons send better people than do countries sending a greater proportion of their total human shipment for reasons of family reunification or as refugees or asylees.
Continuing on that theme, I computed the percentage of migrants gaining residency by way of employment-based preferences by country for '07 from every nation that saw at least 500 of its people granted legal residency in the US during that year. Then I looked at the relationship between this and estimated average national IQ.
The two correlate positively at .51 (p=0). This relationship is attenuated by the presence of a few countries with low average IQs that send lots of workers to the US. Of the 127 countries who had at least 500 people granted legal residency in the US last year, Malaysia, South Africa, and India had the third, fourth, and fifth highest percentages of migrants come via employment-based preferences. The Chinese from Malaysia, whites from South Africa, and brainy Brahmins from India aren't representative of the larger populations in their countries of origin [Razib points out that high educational attainment is a better parameter than any of these designations are]. Removing just these three and looking at the relationship again for the other 124 strengthens the correlation to .58.
If we were looking at the percentage of a nation's population that had the ability to do well in the US, the relationship would be banally predictable. But with the average number of migrants per country coming to a little over 8,000 for the 127 countries, it's only a thin slice of the sending nation's population being looked at. If we take the IQ estimate of 66 for Zimbabwe, that still suggests around 50,000 Zimbabweans with an IQ of 115 or higher. Even the least endowed places could potentially send US employers a sharp contingent.
Yet even with numbers so small (relative to the size of the sending countries), a clear relationship between the percentage of those granted residency due to employment considereations and the average IQ of their home countries exists. Those who've found a place in the US economy are more likely to have come from countries with elevated average IQs. Those coming to swell the size of families already here, as refugees, or as "diversity immigrants" are more likely to come from duller places.