There are two genetic/cultural groups who constitute minorities in Europe. For various reasons they were kept at the margins of society, made liable to restrictions in terms of the trades they could follow, and often hounded and maltreated. In the 20th Century both were slaughtered by German National Socialists.
One of those tribes is well known and highly accomplished, the other less well studied, and with far fewer accomplishments. The contrast is striking. However, explaining that difference must wait for another day. At this point we need to get a better understanding of the abilities of the less well studied tribe, particularly since studies on their abilities are often not published in English, the de facto language of Google science.
I have covered the topic before,
but the London Conference paper brings things more up to date, and carries out a formal meta-analysis.
Dalibor Jurasek has found 38 usable datasets from 7 countries, resulting in a total N = 4468. He concludes that the best estimate of Roma intelligence is IQ 74. This is extremely low. There does not seem to be any verbal bias in the tests; there is weak or no Flynn effect; Spearman’s rule seems to hold.
Below you will find his Powerpoint presentation and, in a move which I hope many speakers will follow, his speaker notes, which give further particulars.
Now we can start working on why the Roma and the Ashkenazi differ in their accomplishments.