It is quite wrong to expect to compare any school's pattern of achievement against National Standards with that of any other school, even for schools with relatively similar intake characteristics, such as in the same decile. There are simply too many sources of variation, leaving each school grappling with the National Standards in ways that preclude fair comparison.
The numerous sources of variation that underlie schools' judgments also mean that any claim of overall improvement or decline in the achievement of New Zealand children against the National Standards will be quite spurious.
The Ministry is pinning its future hopes of making judgments against the National Standards more comparable on an online Progress and Consistency Tool that every school will be required to use. But if the PaCT is intended mainly as a form of national moderation (ie informing other assessment processes rather than itself becoming the assessment tool for making judgments), then it can be expected to be an expensive failure. This is because while it might address some of the sources of variation, particularly the subjectivity of individual teacher perspectives, there are many others it would not be able to get any purchase on.
Another problem with the PaCT is that it will overlook the causes of variability in judgments and deal only with (some of) the symptoms. By failing to recognise the underlying causes of variation, it is likely to allow the Government to ignore the impact of contextual inequalities between schools, for instance, the effects of diverse and unequal intakes and communities, school locations, staffing and other resources.
National Standards may be a government aspiration but they are not national and they never will be while there is so much potential for local variation. It is almost comical - if it weren't so serious - that data representing such variation is being put into the public domain for comparative purposes when there are so many differences between schools in what it actually represents.
Martin Thrupp is Professor of Education at the University of Waikato and leads the Rains project on National Standards.