Fraser Nelson, editor of the Spectator, has written up a paper on Swedish school reforms, which you can download here. I thought it was worth using to quickly flag up two important statistical public policy points.
The context to this is that Sweden has, since the early 1990s, allowed private (including for-profit) institutions to enter the school system – and parallels are often drawn between it and the ongoing reforms of England’s school system. This paper, as Fraser rightly says, comes to the view that increasing the volume of private schools in an area is associated with improved results. Mikael Lindahl and Anders Böhlmark say:
If we transform our estimates to standard deviation (S.D.) units (using the variation across all individuals) we find that a 10 percentage point increase in the share of independent-school students has resulted in 0.07 S.D. higher average educational achievement at the end of compulsory school.