here are an estimated 11,000 supply teachers in Scotland. Few would deny that they play a vital role in enabling the whole school system to function effectively. In the light of concerns about the availability and quality of supply teachers, we were commissioned by the Scottish Executive to research the topic, in order to inform the development of guidelines for schools and education authorities.
Our report, published last week, reveals that school and education authority managers widely recognise the importance of supply teachers.
However, there is little evidence that this recognition is demonstrated through systematic professional support.
The supply teachers frequently referred to themselves as "just supply teachers", implying that they did not expect to be treated on a par with regular members of staff. Why should so many of them experience this feeling of second-class status and what should be done about it?
Part of the difficulty is undoubtedly the confusing diversity of arrangements under which they are employed in the schools of different local authorities. The type of contracts which are offered vary widely, with many not being offered a contract at all - in the most extreme case, we came across a teacher who had been employed continuously in the same school for nearly two years without any formal contract.
Supply teachers who appear to experience the best conditions are those employed as permanent supply teachers, of whom there were 469 at the time of our study, according to the education authorities (and nearly half of these were employed by one authority).
The report finds that while schools were happy with most aspects of the quality of supply staff, there were some anxieties, particularly about aspects of behaviour management and knowledge of recent professional issues. ICT skill was an area where both supply teachers and schools expressed concern.
There was a widespread view that pupil achievement can be negatively affected by the frequent use of supply teachers, yet in very few authorities or schools is there a systematic approach to providing these teachers with an appropriate career structure and relevant professional development opportunities, which would enable them to stay abreast of educational developments and enhance their skills.
The supply teachers themselves fall into three main categories and their own aspirations and motivations differ accordingly.
First there is a group of mainly young, recently qualified teachers, most of whom would much prefer to be in stable employment. Over the past year, the post-McCrone induction scheme has ensured that no newly qualified teachers go straight into supply work. However, the recent study by the General Teaching Council for Scotland shows that approximately 40 per cent of those who completed their induction year in 2003 are now undertaking or looking for supply work - and only 42 per cent have permanent jobs.
Perhaps more worrying than this are the estimated 1,600 supply teachers who qualified "pre-McCrone" and have not been able to achieve full registration because they were unable to secure sufficient consistent work in their subject since qualifying.
The second group comprises experienced teachers who have taken a career break - often for childcare - and see supply teaching as a route back into full-time work or who have made a "lifestyle choice" to take supply work when they themselves wish to, rather than on a regular basis - often because they also have other forms of work.
Among these two groups, most teachers were keen to have improved professional development opportunities and a more structured professional relationship with their employers.
The third group, those approaching retirement or who had already retired, were mostly just as committed to their work in schools, but saw their careers as winding down, and were less enthusiastic about such matters.
While there is not likely to be a "one size fits all" solution, it was widely agreed that successful supply teachers - those who are flexible, adaptable, good classroom managers, good communicators with children and colleagues - are among the most skilled members of the profession.
Where these qualities exist, it is time to recognise them as enormous assets. Where they do not yet exist, it should be our aspiration to develop them.
Ian Menter is professor of education at Paisley University . Merryn Hutchings is deputy director of the Institute for Policy Studies in Education at London Metropolitan University. Other authors of the report on which this article is based are Chris Holligan and Liz Seagraves. The full report is available from email@example.com.