The study is one of the largest of its kind.  It also addresses a crucial flaw in many other studies, by comparing single sex schools to coed private schools, eliminating the "private is better" confounding variable.

6500 women from 225 single sex high schools compared to 15000 women in 1200 coed private high schools, across the country.  It also separates out the Catholic schools, and controls for race, income, etc, etc. 

• 62 percent of s-s students spend 11 hours or more per week studying, compared to 42% of coed school's female students.
• 81 percent of s-s women graduates rate themselves "above average" or in the "highest 10 percent" for academic ability, compared to 75% of coed women graduates.
• 60 percent of s-s women rate themselves "above average" or in the "highest 10 percent"with regard to intellectual self-confidence, compared to 54 percent of coed women.
• 48 percent of female graduates of s-s women rate their math ability "above average" or in the "highest 10 percent" compared to 37 percent of coeds.
  

Two seconds spent staring at this lead to the obvious question:  are they better students, or worse students who are also delusional?  If they spent 11 hours or more studying, was it worth it?

Higher SAT Scores. Women who attended single-sex schools tended to outscore their coeducational counter-parts on the SAT. Mean SAT composite scores (Verbal plus Math) are 43 points higher for single-sex graduates.

I'm not sure if that was meant to be a joke or not. 43 points may be a lot (which it isn't) but it's hardly reason for a group of students to have such a bloated sense of self-esteem that they consider themselves in the top 10% (I look forward to your emails.)  Or, the reverse: 43 points is hardly a reason for another group of students not to have an bloated sense of self-esteem.

Clearly, there is merit in fostering intellectually curiosity and ambition, but things like this:

Single-sex graduates also report more time talking with teachers outside of class, where 37 percent of single-sex graduates reported spending three or more hours per week meeting with teachers apart from class

Seem to me a solid reason to home school.

My point here is not to disparage single sex schools, there may be/are excellent reasons to send a kid to a single sex school.  It simply appears, based on this, one of the largest and most important studies on the question, that self-esteem goes up disproportionately to any concrete metric of achievement.  Contrasting opinions/information are welcome.  I am entirely ambivalent on the question of same-sex education; my own was vigorously no sex, with the resultant negative effects on my own self-esteem.  Now I write a blog.  Plan accordingly.

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