If a manager leaves, the total cost of hiring a replacement (the head-hunter fees, the premium required to entice him and the time it takes him to settle into his job) is usually several times the outgoing person's salary.
The exhibition's co-curators the Filipino anthropologist Corazon Alvina and the Quai Branly's Constance de Monbrison haven't shied away from representing the archipelago's ancient and controversial head-hunter culture through a collection of painted shields and long throwing spears.
Vice-president of the NAHT and Staffordshire primary school head teacher Bernadette Hunter said Ofsted was putting an "intolerable amount of stress" on heads.