Are school leaders born or made? Leadership books abound; more than 30,000 have been published in the past 70 years, and entire university departments are devoted to the subject.
But most pundits aim their books and courses at "latent leaders"; few claim to be able to create leaders from scratch. And some have doubts about the whole industry. "I have many reservations about leadership theory," says Richard Parker, head of Lodge Park technology college in Corby, Northamptonshire. "There are various leadership styles, but how do good leaders recognise which style to use?"
Mr Parker knew training could improve leaders, but suspected that successful heads were as likely to be shaped by their early experiences. A research scholarship from the National College for School Leadership allowed him to test his theory last year.
He looked at five successful secondary heads. All had effected change in challenging schools, but otherwise their situations were very different.
One was an internal promotion to headship; one school was rural, the others urban. One head was black; there were two women and three men. All grew up in secure families where the fathers were ambitious for their children, but none was especially close to his or her parents. Their own education was a mixture of early failure and blissful progress. One was kept on for an extra year at infant school because she couldn't read or write, and another remembered the reaction of some teachers to his problems with literacy.
"You're thick, you're stupid," they had said.
None left school wanting to be a teacher. Four saw a PGCE as a means of deferring the time when they would have to decide what to do with their lives. But they soon realised that teaching was a job they could excel at.
They shared a low boredom threshold, and achieved early promotion. One was a senior teacher at 26. Another was a head of year after three years at her first school. One was a deputy head at 29, the other four made deputy in their early to mid-thirties. "As soon as one job seemed to be getting easier, they started looking for fresh challenges," says Mr Parker. "They hate failing. They set themselves challenging targets, then work single-mindedly to achieve them."
They remembered people who had had a profound effect on them, but the individual wasn't the close mentor advocated in the textbooks. One remembered the head at the school where he was a senior teacher: "She made Margaret Thatcher look like Bo Peep. You were either petrified or in awe of her. I learned never to accept the status quo."
Another said he learned how not to do it from the seven years he spent as a deputy. "The head was an appalling head - the most incompetent, irrational, damaging and dangerous person I have encountered in education. She ruined good teachers' lives because of her rank stupidity. I was perpetually angry and frustrated, but I learned so much about people management by witnessing so dramatically how it shouldn't be done."
Mr Parker's interviews reveal that the heads could be ruthless when required, but the main common denominator, once in office, was a willingness to challenge the status quo and do things their own way. "These people are mavericks," he says. He identified with them, with the importance of key events in their early careers, and that teaching came to them; it wasn't something they set out to do. "I didn't set out to be a teacher either," he says.
He argues that the research has implications for the way heads are appointed and trained. "Competence-based models will produce competence," he says. "We need something more than that. Headship is the engine room of school improvement. Taking a term out and doing the research reminded me just how important this job is."
See the report Passion and Intuition: the impact of life history on leadership on the NCSL website at www.ncsl.org.uk, under 'research scholarships'