Apparently sometimes either a sloppy or an intellectually dishonest writer. Check the links about manipulating data, and the cases of choice with samples seems doubtful.
Still, there is no doubt in my mind that there are genetic differences between the races. It is simply evolutionarily unthinkable. However, they might not be just as large as Lynn posits. If anything, this is a good thing! Especially if he is still right about the relationship between IQ and wealth of nations. This means that there is more hope for Africa. :)