Worldwide, schools are experiencing a severe shortage of teachers - and that translates into far fewer applicants for headship roles. Anecdotal evidence shows that finding principals of the highest calibre is very difficult.
Most heads take on the job because they enjoy it and feel they make a difference. But when you compare heads with middle-managers - in terms of pay and the number of staff we're responsible for - the salary difference is inequitable.
The recruitment problem cannot be fixed entirely by boosting salaries.
Teachers must lift their game and start selling teaching to the world if they wish to be paid more and valued more highly. Self-regulation and a determination to prove that teaching is a profession worthy of great respect are vital to attracting and retaining principals.
Throughout the world, workload is the issue most often mentioned as the barrier to recruiting and retaining principals. There is now much more accountability as well as constant changes in school structure and curricula. Sixty to 80 hours a week is probably standard for principals.
In the western societies particularly, complex problems can cause serious headaches for principals and staff. Custody battles between parents, behavioural problems, "mainstreaming" of children with special needs, global transience that means a much greater racial mix in schools - all these social developments carry hidden costs for schools, regardless of the benefits.
Meanwhile, respect in the community for the profession is low. Students, facing a greater variety of careers, do not choose it for themselves - and teachers, having seen the pressure on their own heads, do not want to lead a school.
How can this be turned around? Experience shows that involving governments can be counter-productive - some say the reason the International Baccalaureate is so successful is because no government has had a chance to meddle in it.
Principals and teachers need to identify problems and find their own solutions. Teachers themselves must behave in a professional manner. They must have excellent training - pre-service and continuing throughout their careers.
They must be role models but also need to show that they enjoy their job and recommend it to their students. They must have professional bodies to raise and maintain high standards in teaching and to take charge of disciplinary actions against teachers who fail to meet these standards.
By raising their performance, teachers can earn high salaries and greater respect.
Principals' associations are springing up throughout the world; through these and their links to the International Confederation of Principals, school leaders and deputies can work on the issues affecting all schools at a global level.
We have got through the stage of competitiveness in education; it's time to move in an international dimension and to share more.
Nola Hambleton is the first woman and first primary principal to be president of the International Confederation of Principals. She was