Average Salaries, 2007-2008
Age	Public	Private	Public Premium
Under 40	$80,600	$47,300	70.40%
40 to 44	$84,900	$54,800	54.93%
45 to 49	$86,000	$55,000	56.36%
50 to 54	$88,100	$59,500	48.07%
55 or over	$91,500	$63,700	43.64%
Average	$86,900	$58,300	49.06%

In a recent CD post, I featured the public sector premium for full-time elementary and secondary school teachers, which ranges from 14% to 102%, depending on experience and education.  The chart above is based on Department of Education data for the salaries of private and public school principals in 2007-2008 based on age.  Compared to public school principals in the age groups above, private school principals have slightly more experience as principals, slightly less experience as teachers, and are less likely to have advanced degrees (Master’s or Doctor’s degrees).  So the age group categories above don’t control perfectly for education and experience, but still show huge premiums for public school principals of 43% or higher, with an overall average premium of 49%.