Why the shortage?

Public school leadership staff who are looking down the road are beginning to warn us that there is going to be a serious shortage of principals.   That information, taken together with the fact that research repeatedly shows the importance of a strong principal in a school, gives one pause for the future of our schools.
One of the reasons for the shortage is the simple aging-out of principals.   As the demographic of principals swings toward retirement age, we begin to lose more and more. Growing older is not something we can fix.    But there are other more troubling signs.
Principals are dissatisfied with their jobs.   It is not the money.   Indeed public school principals, particularly principals of public high schools, do quite well.   The dissatisfaction comes from leaders who are not allowed to lead.   Few things are more frustrating than being held accountable for something you have no power to fix.
It is notable that the problems do not exist to the same extent in private schools.   Before we look at the issues, it is important to note that private school principals generally have the right of first refusal.   That is unless their census is down and the budget needs to be balanced.   In those instances standards are lowered to the extent money is needed.  Getting money and selection out of the way, let's look at other factors.
Public school principals report 29.5% of their students are involved in physical conflict.   This figure is only 7.3% in the private schools.   Those numbers are partly due to initial selection.   But they are also due to the authority of the private school principal to remove a physically aggressive child from the environment whereas the public school principal is forced to contend with behavior policies that are becoming increasingly lenient.
Another huge difference between public and private school principals is influence on curriculum.   Only 43.2% of public school principals report having a major influence on curriculum.   On the other hand, 70.4% of private school principals report a major influence on curriculum.   Curriculum is the meat of what we do in schools.   That, along with instructional technique, are pretty much what schools are about.   If we cannot trust principals to make decisions that will keep their schools safe and then don't allow them to have leadership in what is taught and how it is done, how can we call them leaders.   More importantly, how can we hold them accountable for what is happening in the school.   No wonder they are getting out of the sandbox as soon as they can.   Who would want to play under these conditions.