I looked it up. You're right, Finland does much better internationally than most of the other Scandinavian nations. I would not have expected that result.
One of the reasons I like HN is because sometimes, reading through comments, I see things that just blow my perceptions out of the water. I enjoy going back and reformulating my arguments.
Another problem is that until 2007 the "seminars", the schools for educating teachers, were mainly relics from the late sixties, this having all the obvious implications given the hippie state of DK in those years.
Also in DK through all levels of the educational system from elementary school through university, the main focus is on the students who are at the bottom of the skill spectrum.
I think the biggest difference overall was a lower amount of underachievers in Finland.
I don't know if the Finnish school system is that super great. Maybe you get some knowledge of this and that, and gain a work ethic, but one could teach the kids so much more about life than that would help them a lot later on.
Also I've heard that talented / energetic people have more opportunities to go extra far elsewhere (I've heard positive stuff from California), while here it's more egalitarian, at least at normal schools.
Our kids start school the year they turn seven and the school days are shorter than elsewhere.
Finland's technological and industrial output clusters with Sweden, Denmark, and Norway to a far greater extent than it does with countries outside Northern Europe.
In the same way, when you look at the TIMSS, intra-European variance exists and is nontrivial, but European and East Asian nations do tend to cluster together quite a bit:
http://nces.ed.gov/pubs2009/2009001.pdf
See Table 3 on page 19. Top 5 countries in grade 8 in math: Taiwan, South Korea, Singapore, Hong Kong, Japan. The very top European countries are towards the lower end of the East Asian distribution in math, and are only close in 4th grade (before puberty onset).
Of course, nothing ever happens.