How National deceived itself over class sizes

Understanding how National got into such a mess over class sizes after Budget 2012  - trade-offs, downsides and backdowns.

John Hattie's book Visible Learnings brings together over 800 meta-analyses to rank 138 influences on educational achievement. Five make the students worse off. Some have very little effect. For instance class size is 0.2 –  Hattie is dismissive of anything below 0.4 on his measure – but its effect is still positive. There are 105 other influences ranked above it.

The ranking method involves measuring the share of the total variation of achievement which can be explained by the particular influence. Hattie suggests that  the effects of reducing class size may be small, because teachers do not adapt their teaching styles to different circumstances. He keeps coming back to the style and quality of teaching as key points for improving educational achievement. The implication is that by putting more effort into the teachers we can get a bigger return from smaller class size. Even so the research evidence supports the public intuition that smaller classes are better, even if the teachers do not change.

An economist has a doubt about the usefulness of the Hattie measure for public policy purposes. It is not that it is wrong, but that it ignores costs. Reducing class size is probably one of the most expensive changes among the 138 influences. It would be good to have the Hattie list ranked by cost-effectiveness; it is likely that class size would be ranked much lower, perhaps near the bottom, just above the five duds. Because it is so expensive, the cost effectiveness of reducing class size is near enough to zero. Some of the influences that Hattie ranks below class size are almost costless to implement. Better to do them; yet it's better again to do those which are higher and are near costless too.

So how did we get into the muddle in which the government said that, quite contrary to the evidence, there are no gains to be made from reducing class size and no losses from increasing it? What happened is indicative of a wider problem the government is facing.

The 2012 budget had a tight expenditure restriction as a part of the government strategy of eliminating the internal deficit without increasing taxation. What ministries were allowed to do, though, was reallocate within their capped expenditure.

Suppose a ministry had a new very cost-effective programme but there were no extra funds to implement it. It could obtain the funds by reducing spending on a low cost-effective program. That is what the government was trying to do in its education budget. In order to spend more on teacher training, it proposed reducing class sizes to fund it.

That seems to an economist to be a sensible trade-off to contemplate. But to be honest, the trade-off has to admit that educational achievement would be reduced from larger classes, although it is likely to be more than offset by gains from better teacher training. The public might not like the  cuts, but it would be clear to them what was happening.

However all governments in general – and the current one in particular – are unwilling to admit that their actions may have downside effects even if the overall impact is positive. So in this case it had to deny that class size mattered – contrary to common sense and to the research evidence. There was a plethora of releases before the budget announcing new programs with benefits, but nary a mention that they would be funded by closing other programs. As a rule the bad news will trickle out and the public will be grumpy, long after the benefits of the new programs are thought to be normal.

I really don't know how much the government is aware of what it is doing. Very often deceiving the public – such as there are no downside effects even when they are substantial – ends up with the politicians deceiving themselves. That is what happened with the proposed reductions in class size. The government was totally unprepared for the uproar which followed, and had so forgotten what it was doing that it was unable to cope with the public agitation; hence the backdown.


Footnote: Immediately below class size in Hattie’s ranking is charter schools. It might seem then that, providing the initiative has a very low cost, they should be proceeded with. I am, however, reluctant  to come to that conclusion. The research is from the United States which has a very different educational structure from New Zealand, and its findings may not transfer here. Indeed I thought long and hard before I concluded the overseas evidence about class size probably applied to New Zealand. Even so, if Hattie is right and the key is how teachers adapt, it is possible that ours adapt better than those in the jurisdictions where the research was done and the cost effectiveness of reducing class size is lower here.