KEY POINTS:
A staunch defender of the Cambridge exams begged to differ with me after last week's column.
NCEA, he wrote, is social engineering, whereas Cambridge "is not just for the self-serving middle class but is also for the underclass that has pride, dignity and a desire to break the shackles of identity politics".
All right, so everyone's an expert on schooling - and some of them have written to tell me so. But my correspondent had taught for 25 years in poor schools, and now teaches at a decile 3 high school that, he says, has gone from being the poorest academic performer in its district to being the most academically successful, in Cambridge, NCEA and Level 4 Scholarships.
More impressively, "our last ERO report showed we had one of the top Maori students' performances in the country - the school is 57 per cent Maori and some of our top Cambridge performers are Maori".
I wondered how the introduction of the Cambridge exam could have made so much difference. Could there have been other factors involved?
Well, yes, as it turned out. The school is attracting more middle-class students, its roll has risen dramatically, and there is "a 100 per cent buy-in by teachers" into Te Kotahitanga, a Waikato University initiative that focuses on how teachers relate to Maori students.
"The school ethos is whanau. We pride ourselves on the access that community have to our school. Our principal is female and Te Arawa - a real treasure. Close to half our staff are Maori.
"Passionate educationists like myself and others teach on the weekends. I regularly have between 25 to 35 students who come in on Sundays between 9am and 1pm to do extra practicals and practice exam techniques. We work. Work ethic is the key."
Which proved my point, I thought. The difference wasn't Cambridge at all, but the kind of extraordinary effort it takes to help low-income students succeed, not least the devotion of "passionate" teachers prepared to sacrifice their weekends and put some effort into understanding their students. All of which accord with the findings of, for example, Te Kotahitanga here, and the Achievement Gap Initiative at Harvard.
As director Ronald Ferguson told the Harvard Education Letter recently, success for poor, black kids requires teachers who understand them.
Their research shows "if kids don't think that the teacher both loves to help them and holds them to a high standard, their behaviour can deteriorate and their engagement can deteriorate".
Still, my correspondent was right about NCEA being social engineering. If we want to engineer more Maori, Pacific and low-income students into university, and I think we do, we're better off trying to improve NCEA rather than returning to the old system of end-of-year exams.
It's typical of the education debate that the agenda has been set by the middle classes, who can - and do - take care of themselves. Yet the most critical - and least discussed - challenge in education is the underachievement of particular groups: Maori, Pacific and the poor.
These groups inhabit the long tail of underachievement identified as a major threat to prosperity and social cohesion.
As a 2005 OECD report said, "The foundation of human capital is laid down in schools and it is obviously more cost effective to provide all school-age children with an excellent education than dealing with the social and economic consequences of school failure through remedial efforts with adults."
But, of course, that's easier said than done. As the principal of a low decile South Auckland school complains, schools are told by the Government to "fix Maori underachievement", but they're not told how.
No one's come up with a silver bullet solution. And it's complex. It's hard to separate the influence of ethnicity from socio-economic status when so many Maori and Pacific people have low incomes. What's clear is that there aren't many middle-class Maori and Pacific people at the bottom of the achievement tables, just as there aren't many middle-class boys underachieving.
Which brings me to Starpath, an Auckland University-led project that's just released a study providing evidence of the effectiveness of NCEA, particularly compared to the Cambridge exams.
The finding that's attracted the most attention is that NCEA is five times better than the Cambridge exam at predicting the success of first year students at Auckland University, the most likely reason being the similarities between NCEA and university study, both of which require ongoing assessments.
But, as Professor John Hattie points out, the big news is that NCEA gives universities a tool for identifying bright Maori, Pacific and other low-income students who would miss out on university under both the old exam system and Cambridge.
If quality rather than quantity of NCEA credits is taken into account, 16 per cent more Maori and 14 per cent more Pacific students would qualify for entry to university, most from low decile schools. Proving that NCEA is on the right track.