I live in a European country (not Scandinavia) that does have strong social safety networks in place and we still look at Finland and scratch our heads because our students don't achieve the same results by a long shot.
Some things that appear to be truly specific to Finland:
A very homogeneous society, not just socially, but also ethnically and linguistically, apart from an area in which people speak Swedish. Very little immigration compared to other industrialized countries (certainly very little unskilled immigration), few language learners.
Most of the country is, again compared to other industrialized countries, fairly rural and sparsely populated. There is some evidence why this makes a tangible difference (I've never seen Finnish results in Helsinki compared to rural districts, though).http://blog.newsweek.com/blogs/nurtu...er-scores.aspxhttp://blog.newsweek.com/blogs/nurtu...-airports.aspx
No academic tracking until 10th grade. In combination with the points mentioned above, this makes for very socially integrated schools, that is there are no schools where low socio-economic background, language-learning students congregate. There is some evidence that schools that do not have a critical mass of students with favourable factors in their backgrounds (and I read that experienced educators say it must be more than 50 %) pull everybody down. As soon as the critical mass is there, it pulls everybody up. Meaning it's hard to find a struggling school in Finland. (However, they concede they may not offer enough challenge for very advanced and gifted students and are working on that).
And apparently, one should not discount the fact that Finnish is a phonetic language, reading it is easy to learn (haven't a clue myself, but it's what I read) and a lot of kids pick it up before formal schooling, some helped on by watching subtitled English-language kid TV - and none of that's Waldorf, by the way!
Very dedicated teachers, support staff in place (teaching is an extremely respected profession and competition to get into teacher training schools is fierce).
So, some of these factors can be replicated in other countries, but the society cannot. Canada does very well in those tests, too! I suppose they have some similarity with Finland, and I think both what kind if immigration you have (not just numbers, it's skilled vs. unskilled, heterogeneous or homogeneous as in some European countries) and the support you have in place for second language learners is HUGE.