Why we’d not trust Kate Pickett with the teaspoons

Those with decent memories will recall The Spirit Level, where all that ails society is accorded to inequality itself. We’ve an update on that:

But what actually happened to inequality and GDP over this period? On Pickett’s own preferred measure, the Palma ratio, inequality peaked in 2008 and has fallen considerably since then, as the tax system has become significantly more progressive. Meanwhile, growth in GDP has been very slow compared to the previous two decades. If you’d asked Pickett in 2010 whether she’d have accepted this trade – much slower growth in GDP in return for more progressive taxation and lower inequality, she’d presumably have jumped at it. But now, like most of the rest of us, she’s less than happy with the results.

This is a point that we around here have made a number of times. Given that inequality has fallen but we’re no happier, nor bettrer off by the Spirit Level measures, then and therefore inequality is not the root cause of all. Fair play to Jonathan Portes - much as that sticks in the craw - for pointing this out here in the review of the new book.

But the real reason we’d be counting the teaspoons is that use of the Palma ratio. For in that earlier Spirit Level the measure used was the Gini Index. And when people change their measure but keep the message - on the grounds that by the old and original measure the concept did not work out - we do get more than a little concerned about the truth of the message itself. It’s like switching from inches to centimetres and hoping to tyhen show that no, really, the high jump is taller than the pole vault.

We don’t trust those who keep changing the metric instead of altering the conclusion.

Tim Worstall