'The F Story about the Great Inflation'

Simon Wren-Lewis:

The F story about the Great Inflation: Here F could stand for folk. The story that is often told by economists to their students goes as follows. After Phillips discovered his curve, which relates inflation to unemployment, Samuelson and Solow in 1960 suggested this implied a trade-off that policymakers could use. They could permanently have a bit less unemployment at the cost of a bit more inflation. Policymakers took up that option, but then could not understand why inflation didn’t just go up a bit, but kept on going up and up. Along came Milton Friedman to the rescue, who in a 1968 presidential address argued that inflation also depended on inflation expectations, which meant the long run Phillips curve was vertical and there was no permanent inflation unemployment trade-off. Policymakers then saw the light, and the steady rise in inflation seen in the 1960s and 1970s came to an end.

This is a neat little story, particularly if you like the idea that all great macroeconomic disasters stem from errors in mainstream macroeconomics. However even a half awake student should spot one small difficulty with this tale. Why did it take over 10 years for Friedman’s wisdom to be adopted by policymakers, while Samuelson and Solow’s alleged mistake seems to have been adopted quickly? Even if you think that the inflation problem only really started in the 1970s that imparts a 10 year lag into the knowledge transmission mechanism, which is a little strange.

However none of that matters, because this folk story is simply untrue. There has been some discussion of this in blogs (by Robert Waldmann in particular - see Mark Thoma here), and the best source on this is another F: James Forder. There are papers (e.g. here), but the most comprehensive source is now his book, which presents an exhaustive study of this folk story. It is, he argues, untrue in every respect. Not only did Samuelson and Solow not argue that there was a permanent inflation unemployment trade-off that policymakers could exploit, policymakers never believed there was such a trade-off. So how did this folk story arise? Quite simply from another F: Friedman himself, in his Nobel Prize lecture in 1977.

Forder discusses much else in his book, including the extent to which Friedman’s 1968 emphasis on the importance of expectations was particularly original (it wasn’t). He also describes how and why he thinks Friedman’s story became so embedded that it became folklore....