The book talked about the difficulty in making comparisons because private school students tend to come from families of a higher socioeconomic level than the average public school student. So statistical methods were employed to allow for these differences. The article also included reactions from both sides of the debate--which I appreciated seeing and reading about.
I am a public school employee--currently in my 26th year. I attended public schools K-12 as a child. I'm not rich and I've never been rich. Clearly, I have had very little experience with private schools. My wife taught in a private school for 11 years, and I have had some contact with private schools in my current position. Still, it would be fair to say that my exposure to private schools has been limited. (And I write a blog about the good things in public schools.) Hence, I am likely to be biased toward the benefits of public schools.
My thinking is that it seems that public school teachers are (often) better paid than private school teachers. I don't know if this is a fact, but my limited experience has shown this to be true. If you have a teacher who is highly-qualified and much sought after by both public and private schools, I would think that the teacher would go for the job that paid more money most of the time. Also, I wonder if public school teachers get more training on teacher strategies and educational technology??? Lastly, I know that public schools spend a lot of time and money on students with special needs. I don't know if private schools have the same abilities to help students with special needs.
I know it isn't true that all private school students come from rich families. But it probably is true that private school students (as a group) are richer than public school students (as a group). And we know that richer students do better in school than poorer students. This leads to the perception that private schools are better than public schools. But what it really tells us is that richer students do better than poorer students--which is something we already know.
It is good to see that there is some scholarly evidence to show the benefits of a public school education. Thanks Mr. and Mrs. Lubienski; and thank you to Ed Week for the article.