Most people would agree that fairness means that equal things get treated equally and different things get treated differently. In the schooling sector, the current funding system by deciles is one such attempt to be fair.

The system was designed on the premise that schools do not all serve the same kinds of students and that some schools need additional support to help their students reach their potential. It thus attempts to level the playing field by grouping schools by socio-economic status. In this way, schools with higher proportions of students from low-socio-economic areas receive more government funding.

Unfortunately differentiating schools by deciles to assess their needs has often been misunderstood. Schools, parents and the media sometimes took it as a sign of the quality of teaching and leadership in a school, which it clearly is not. Generally the lower the school decile, the worse the school was perceived.

It was therefore encouraging to learn that the Ministry of Education is looking to review the funding system.

Though the Ministry has not confirmed specifics beyond that the current model is being reviewed, recent media reports suggest that the new model will address two things among others. One, funding will be better targeted to individual student-needs rather than continue to group all students in the same school as requiring the same level of support. Two, it is hoped that the removal of school deciles will do away with the inappropriate use of deciles as indicators of how good a school is.

This is laudable and it appears to be generally welcomed by the schooling sector.

However, the new model will not automatically eliminate the need for observers to use it as a measure of school quality. It could be similarly misused. Indeed, there have been commentators expressing such fears.

But these reservations also present an opportunity to shift the debate on how to evaluate the quality of our schools.

The Ministry has identified the risk factors behind why students underachieve, and may allocate funding to schools based on this information. Schools may get additional funding for students whose parent(s) had been to prison; where they or a sibling had experienced child abuse; whose family relied on long-term welfare; or where their mother had no formal qualifications.

But largely missing in the commentary is how the Ministry could use this new information to better understand how schools are doing.

The way that the performance of schools and teachers is currently reported does not show how much progress students have made when compared to students with similar backgrounds. For example, the 5 year-old who did not have any early childhood education and whose parents did not read to him may struggle when compared to one who had both experiences. Yet, the current yardsticks used to judge schools expect all students to achieve at the same pace, even if they begin school at different starting points.

But now that the Ministry has laudably identified the risk factors, would it not make sense that the factors be considered when measuring and reporting on students' progress and achievement?

If the level of progress a student should make in a year's time could be predicted, there would be a better basis on which to measure school and teacher performance.

For a simple illustration, imagine if a student who is 'at-risk' is expected to make eight months' worth of progress in a year's time. A teacher whose students progressed by at least that much would have been effective, even if the students' overall achievement still puts them below average national performance.

There is ample potential for using the new information to inform a better school improvement approach. For one, there would be improved indicators to identify the schools and teachers that get the most out of certain kinds of students. The data would inform student sorting so that students are better matched to schools and students better matched to teachers. Equally important, the approach would allow for early identification of teachers and schools that need to improve.

That said, this is a delicate process. The Ministry is dealing with people, careers, communities and potentially powerful unions.

The thinking behind a new funding model should be expanded so that it too does not end up being used as a shortcut to judge quality as the current decile system has been.

The new information on students has the potential to give all students a fair chance to succeed and will better support parental choice. In the same vein, it presents an opportunity for schools and teachers to be compared more fairly.