[ODP] Immigrant GPA in Danish primary school is predictable from country-level variab
You note that Pearson correlation is robust to non-normality. But I'm sure about what I say. Andy Field (2009) writes, in "Discovering Statistics Using SPSS ", for example :

Pearson’s correlation coefficient was described in full at the beginning of this chapter. Pearson’s correlation requires only that data are interval (see section 1.5.1.2) for it to be an accurate measure of the linear relationship between two variables. However, if you want to establish whether the correlation coefficient is significant, then more assumptions are required: for the test statistic to be valid the sampling distribution has to be normally distributed and as we saw in Chapter 5 we assume that it is if our sample data are normally distributed (or if we have a large sample). Although typically, to assume that the sampling distribution is normal, we would want both variables to be normally distributed, there is one exception to this rule: one of the variables can be a categorical variable provided there are only two categories (in fact, if you look at section 6.5.5 you’ll see that this is the same as doing a t-test, but I’m jumping the gun a bit). In any case, if your data are non-normal (see Chapter 5) or are not measured at the interval level then you should deselect the Pearson tick-box.
The new immigration report has come out. Every year the Danish Statistics Agency releases a report on immigration in Denmark. This year they have included quite a lot of more useful data. As a new thing, it includes GPAs for some countries of origin, but only for a small number and only for second generation. I will update the paper with these new data and analyses of them.

http://www.dst.dk/da/Statistik/Publikationer/VisPub.aspx?cid=19004

To give some perspective, could you provide the standardized differences with respect to the indigenous Danish norm? This would better allow me to judge the generational effect. Is there no way to estimate how mix generation the first sample was? For example, comparing the first and second sample sample size.

One problem with interclass correlations is that it doesn't take into account the absolute differences. Thus, you might have a national-IQ second generation GPA correlation of 1, with trivial actual differences. Thus, providing standardized differences is helpful.
Emil,

I notice that girls do better than boys in the second dataset. Do we see the same sex difference in the first dataset or does the sex difference increase as one goes from the foreign-born to the Danish-born?
MH, any further objections to the revised version? You previously approved a prior version.

Can other reviewers comment on this submission?

I need to know which pages and/or sections have been modified.
One problem with interclass correlations is that it doesn't take into account the absolute differences. Thus, you might have a national-IQ second generation GPA correlation of 1, with trivial actual differences. Thus, providing standardized differences is helpful.

Emil, could you address this concern and the ones mentioned by PF and MH? Thanks.
John,

I can calculate the predicted IQ gap by generation and age as well, but have not done so. This one should be compared with GPA to see how the estimated general intelligence difference compares with the grade difference.

Can you include a brief comment on this?
The first dataset concerns 9th grade pupils both generations in the years 2007-2009.
The second concerns 9th grade second generation pupils in the years 2009-2013.

I fetched population data for both of these groups from the DST.

I had to estimate some missing countries e.g. Czechoslovakia, from Czech Rep. and Slovak Rep.

Output is:
09-13 group, 2nd gen:
Mean IQ: 87.2
IQ SD: 16.3

07-09 group, mixed gen:
Mean IQ: 87.3
IQ SD: 16.7

So, the IQ d gap is a bit less than 1 according to the modeling, depending on which SD one uses to calculate d.

What is the correlation of IQ x GPA in primary school? Perhaps .5? If so, these results are in the right ballpark.

OK, add a comment about this. There is nothing more that I would like you to add. After you make the appropriate additions, I approve publication. (Generally. I feel that all of the ST hypothesis papers should discuss generational effects.)