Everybody knows that inequality has been rising in New Zealand since the reforms of the 1980s. We know this because the media and politicians tell us so. The last few years have shown a sharp rise in the number of newspaper articles devoted to inequality. If you search through the Hansard, you will find that inequality was mentioned about a dozen times a year prior to 2007. Since then, Hansard mentions skyrocketed: first to around 50 a year, then reaching 99 in 2014. Nigel Latta even put on a documentary. Inequality is clearly seen as a serious and rising problem.

The only problem with that is that the data says otherwise.

Work by both the Ministry for Social Development and Treasury shows that while inequality rose through the reforms of the late 80s and early 90s, it since plateaued or even dropped. The Ministry of Social Development concluded that there has been no rise or fall in income inequality in the last twenty years across a range of measures.

Treasury work by Christopher Ball and John Creedy found, in addition to a mild decline in Gini measures of income inequality since 2001, there has been substantial reduction in consumption inequality. Inequality in consumption has, since 2010, been rising mildly, but is currently below 1984’s level.

So despite the great and rising furore over inequality, there is absolutely no basis for it in the data. Further, New Zealand’s levels of inequality are decidedly middle-of-the-road when we look internationally.

What happens when you tell people about it? Well, derp. Derp is the technical term for the sheer refusal to change one’s beliefs in the face of evidence. The 149 online comments on the Fairfax article suggested that New Zealand’s derp levels might even be at a crisis level.

Everyone is entitled to an opinion, but nobody is entitled to his own facts. Whether statistical measures of inequality have been rising or falling is something that does not really leave room for disagreement. It can be perfectly consistent for an honest egalitarian to say that current inequality levels are too high despite that consumption inequality is well down. But reckoning that the data must be a Treasury conspiracy is not intellectually honest. It is derp.