Leadership is to this decade what standards-based reform was to the 1990s.

Put another way, if you want to boost achievement, a strong standard-based reform strategy can take you so far; but if the aim is to accomplish deeper, continuous improvement, leadership at many levels is required.

The problems schools face in advanced countries include:

* The need to raise the bar and close the gap between high-performing and low-performing students and schools in literacy and numeracy.

* The need to focus on the socio-emotional development of children in the early years.

* The difficulty of engaging pupils in learning.

* The problem of maintaining a teaching and learning focus in the face of overload and multiple initiatives.

* Failure to capture the hearts, minds and vitality of teachers and leaders in the service of continuous improvement.

* The gap between many parents and schools in aligning their efforts to improve learning.

* The extreme difficulty of changing school cultures into collaborative professional learning communities.

The first-level response to these problems has been to tackle literacy and numeracy. In so doing, England, for example, has boosted its proficiency scores of 11-year-olds from the mid-fifties in percentages to the mid-seventies since 1997 in both literacy and numeracy.

During this period the focus has not been on basic leadership (school heads), but on literacy leaders, at both school level (literacy co-ordinators and consultants) and at local authority and national level.

But as the new century began, governments around the developed world concluded that school leadership had been neglected. Within the space of a year or two, England established the National College for School Leadership, the Wallace Foundation and several other US-based philanthropic entities made leadership their top priority, and virtually every state department in advanced countries passed new policies for developing and certifying educational leaders.

These are steps in the right direction, but there are two fundamental limitations in the strategies employed. First, they are too confined to achievement scores of pupils; second, they suffer from what I will call the individualistic fallacy.

As to the first limitation, consider Jim Collins’ research, Good to Great, in comparing “good” companies (strong performance here and there) and “great” companies (sustained economic performance over a minimum of 15 years). He found that good companies had what he called “effective leaders” (who catalyse commitment to vision and standards), but great companies had “executive leaders” (who build enduring greatness). This is a crucial distinction when applied to educational systems. Many school leaders are preoccupied with the bottom line of pupil achievement scores. At best, many such heads will represent short-term, non-sustainable reform. Instead, the success of heads should be measured on how many leaders they have developed who can help their schools progress even further. Student achievement should be part of the picture, but establishing conditions for continuous improvement is equally important.

The second limitation - the individualistic fallacy - is more subtle.

Initial strategies to address the leadership problem have focused on new qualifications, incentives to meet new standards, and increasing salaries for school heads. The assumption is that we can change schools by providing new leadership and that the way to do this is by changing individuals. Yet this is only part of the solution.

Equally important is to change the conditions under which school leaders work: the resources available, the opportunity to interact with other leaders across schools, and above all the potential to make a difference in difficult circumstances. Otherwise, good leaders will not come in large numbers nor will the best ones stay.

Finally, deeper change cannot rely on a few good leaders - it requires large numbers of leaders who find the challenge exciting but not beyond their reach.

Michael Fullan is professor of education at the University of Toronto, and author of “The moral imperative of school leadership” (Corwin Press) World Class Leadership, 16-page special supplement