Nearly four years ago, governing bodies were given an important role - to appraise the performance of their headteachers. They were not left to do the job alone, though. External advisers, who are often practising heads and other senior educationists, were provided - free - to give support and advice.

Last summer, my colleagues and I interviewed 18 external advisers who had visited between 30 and 40 schools in each of the first three years of the new system. We wanted to know how they felt the performance management process for headteachers was working and what heads and governors do to make it a useful process.

Overall, the advisers felt they had made a real difference to the process, and had helped empower governing bodies to tackle under-performing heads.

But where ineffective heads were controlling weak boards, the external experts’ advisory role limited their impact.

Under the performance management process introduced in September 2000, governing bodies are expected to: appoint two or three of their number to appraise the head; appoint an external adviser; and ensure that objectives are agreed for the head. External advisers, chosen and paid by Cambridge Education Associates and trained by the Centre for British Teachers (all on behalf of the Department for Education and Skills), should:

* write a short pre-visit report, based on documents sent by the school, such as development plans and inspection reports;

* visit the school to meet the head, advise the governors, and help agree and write up the head’s objectives;

* send a post-visit report to CEA.

The external advisers we talked to were very clear that their primary role was to advise the governors. But they also felt they provided support for heads, for example by encouraging them to discuss things they wouldn’t mention to anyone else and to be more adventurous in their choice of objectives.

They also saw themselves as counsellors, facilitators, mentors, honest brokers, coaches and governor trainers. But they disliked being seen as inspectors, and there is some concern that they are now being asked to make judgments on the head’s overall performance without sufficient evidence.

Being objective outsiders is key to their role.

The response of governors and heads to performance management has been positive, say the external advisers. In the first year, there was some suspicion and defensiveness.

Governors had some apprehensions, stemming sometimes from lack of experience, not knowing enough about the school, or their own concerns about making an assessment of a senior professional. But all the advisers said the overwhelming majority of heads and governors now respond positively to the process, as they recognise its value to their schools.

To be worthwhile, performance management must make a difference. That difference is likely to be greatest where the head’s leadership is less than satisfactory. Overall, between 5 and 10 per cent of heads visited by the external advisers were described as ineffective.

Sometimes the governors were aware of the weaknesses, sometimes not. An early warning sign for the external advisers would be if the school supplied poor or minimal information at the start of the process. Another give-away was the head suggesting low-level or easily achieved objectives.

Sometimes the external adviser had been able to help improve things by working with the head and governors on setting more challenging targets, or giving governors the confidence to tackle their head’s under-performance.

Where the relationship between the governing body and the head was too “cosy”, however, and the governors were unwilling to tackle the head, the impact of the advisers was severely limited. Where there was an ineffective head controlling a weak governing body, external advisers felt it was almost impossible to make a difference because of the very short time they spent in school (one visit per year averaging three to four hours).

Schools can use the same adviser for up to three consecutive years. But some found they weren’t asked back if they had tried to challenge the status quo. The three-year rule itself has been controversial. Most advisers would like longer with their schools - as would many heads and governors. The external advisers felt time improved their understanding of the school’s context and strengthened the relationship and trust with heads and governors - making it possible to raise difficult issues.

Governors’ monitoring of the head’s progress throughout the year was by far the weakest part of the process, according to external advisers. Even when dates for interim meetings were set well in advance, they often did not take place or minutes were not kept. Advisers suggest that evidence-gathering by governors remains weak and that heads are not always good at providing it. Poor monitoring during the year often results in slippage on meeting the targets.

Overall, though, advisers felt the process was effective and offered good value for money. As outsiders with no axe to grind, they have contributed significantly to the performance management of headteachers.

Schools minister David Miliband has talked of creating a “single conversation” for heads, covering performance management and other subjects, and conducted with another “critical friend” head. Whether external advisers will expand or disappear remains to be seen.

Peter Earley is an external adviser and works at the Institute of Education, University of London. His latest book (co-written with Sara Bubb), Leading and Managing Continuing Professional Development, is published by SagePaul Chapman.