What kinds of things matter for student achievement? Is it class size, school journals, the school building, or a flash new gym?

These may play a role at the margin, but they pale in significance next to what research conclusively shows is the most important in-school factor for student achievement: the teacher.

On Monday, The New Zealand Initiative releases its first education report on teacher quality, and it comes at quite a precipitous time. As the ageing teacher workforce moves into retirement, New Zealand needs to not only replenish this workforce but attract the best and brightest into the teaching profession. And then, for teachers to develop to their full potential and to retain the best teachers, teaching must be a challenging and rewarding career.

Yet our report has uncovered some major problems in the career development of teachers in New Zealand. Aside from going into school administration, there is little opportunity, challenge, and recognition for a teacher to further develop their skills and capability. Also, the maximum salary point is reached after eight years. It is obvious what kind of signal this sends: teachers have reached their maximum ability after eight years.

There are also some major concerns about the status of the teaching profession, and low morale among teachers. A survey of secondary school teachers by the New Zealand Council for Educational Research found that teacher morale fell to 57% in 2012, from 70% in 2009, and of major concern, a 2006 report found that teachers were so negative about their own profession that they were putting students off a career in the profession.

The obvious benefit of offering teachers a positive climate to work in, and opportunities for development, is improved student learning. But also, by improving the career paths of teachers, we can start a virtuous cycle; attracting a larger pool of candidates to the profession, enabling greater selectivity, thereby raising the level of talent within the system and the status of the profession even further.

Arguments abound that we can’t lift the status of teachers here to the same levels as top-performing education systems like Singapore and Finland because of the cultural value placed on teachers in those countries. But New Zealand also has a good platform to start from, having one of the leading education systems worldwide with some excellent teachers, and excellent potential, already in the system. Like Singapore and Finland, policy can be designed to build on the excellence that already exists.