> there are some underlying factors skewing these results, such as: > * grammar schools are more likely to be single-sex > * co-educational schools have a higher proportion of poorer pupils > * girls are more likely to get good results
Also note that both of your comments show that people in a position to choose, are choosing single sex schools for their daughters and getting better outcomes on average.
Lastly, while the article mentions some caveats around selective state schools, the other side of that is the UK has many single sex comprehensive schools. We should not ascribe too much weight to the caveat.