According to a 2004 study by the Thomas B. Fordham Institute, public school teachers send their own children to private schools at a higher percentage than families in the general public.

Conclusions from the Fordham study:

Similarly, we can assume that no one knows the condition and quality of public schools better than teachers who work in them every day. Teachers, it is reasonable to assume, care about education, are reasonably expert about it, and possess quite a lot of information about the schools in which they teach. If these teachers are more likely than the general public (which may not have nearly as much information or expertise in these matters) to send their own daughters and sons to the public schools in which they teach, it is a strong vote of confidence in those schools. If they do not, then we might reasonably conclude that those in the best position to know are signaling a strong ‘sell’ about public education in their communities.

The data again show that urban public school teachers are more likely than either urban households or the general public to send their children to private schools. Across the states, 12.2 percent of all families (urban, rural, and suburban) send their children to private schools —a figure that roughly corresponds to perennial and well-known data on the proportion of U.S. children enrolled in private schools. But urban public school teachers send their children to private schools at a rate of 21.5 percent, nearly double the national rate of private-school attendance. Urban public school teachers are also more likely to send their children to private school than are urban families in general (21.5 vs. 17.5 percent).

Source: http://www.edexcellence.net/doc/Fwd-1.1.pdf