After decades of rising raw scores on IQ tests given to military conscripts in Denmark and Norway, the scores stopped rising about a decade ago. This raised the question of whether the Flynn Effect had played out, or whether the increasing number of lower IQ immigrant youths was the cause. The original papers did not distinguish between the two groups, so that remained uncertain.
Modern Tribalist cited the Copenhagen Post:
Draftees with immigrant background stand a worse chance of passing the required intelligence test then ethnic Danes, the Danish Defence Academy said in a report on Monday.
The report, which based its conclusions on 22,646 reviews of conscripts tested between September 2003 and June 2004, found that 28 percent of draftees with an immigrant background failed the military's intelligence tests, compared with only seven percent of ethnic Danes, national television news channel DR reported.
A quick use of the Normdist function in Excel suggests the passing score would be around an IQ of 78 (by law, the U.S. military can't induct anyone who scores under 80), and if ethnic Danes average 100, then youths of immigrant ancestry would average around 87, which sounds about in line with other reports on immigrants in Europe.
However, one of the authors of the first study on the end of the Flynn Effect in Denmark says that their next paper will break out ethnic Danes. They've seen falling raw scores among ethnic Danes in recent years.
So, it looks like the Flynn Effect might be coming to an end. Yet, we still don't understand its causes.