NGDP data revisions means targeting it is “totally impractical”, really?

A James Alexander post

Danny Blanchflower, the enfant terrible of the Bank of England when he was for a time on its rate-setting Monetary Policy Committee, tweeted here that NGDP Targeting was “totally impractical” because it was a figure that was so subject to data revisions.

Well, first off, revisions don’t matter to Market Monetarist advocates as the “Market” bit of MM refers to the theory that you should target expectations for NGDP Growth. Scott Sumner has argued for a market in NGDP Futures so accurate market forecasts of NGDP growth could be used. This proposal is not much of a leap for standard macro theory that argues you control inflation by targeting inflation expectations. So it’s no big deal to target forecasts, every macro-economist should get that bit.

Market Monetarists are highly sceptical of inflation expectations as measured purely in surveys. The public has little understanding of the term inflation. Although the public sees their shopping basket go up and down in cost it has only modest relevance to the central banks that like to target core inflation, i.e. excluding volatile food and energy. On saner days central banks actually target the measure of inflation that gets them from NGDP to RGDP, known as the GDP Deflator. This figure often runs well below measures of consumer inflation. A good discussion on the good reasons why this happens is here.

Consumers would also have little view on NGDP, of course, if that were targeted. They would roughly see one large element though, in aggregate wage or income growth. This is because NGDP (and therefore RGDP) can be measured by adding up all the income in the economy, via the “income method”. The two other ways to measure NGDP are the self-explanatory “expenditure method” and the very tricky “output method”. Of course, I don’t have to explain this to expert economists like Danny Blanchflower.

Second, NGDP should, in theory be more reliable to measure since RGDP is based upon NGDP. Any errors in NGDP will, de facto, be in NGDP. However, RGDP errors are then compounded by errors in the deflator. It is therefore impossible for RGDP to be more reliable than NGDP.

The question is then whether NGDP is more or less prone to error than “inflation” measures. Well, NGDP only has one definition, so that certainly helps, inflation many. The infamous switch in the UK from RPI to CPI as the main method was certainly a major revision to method and certainly sowed huge confusion. It still does cause problems as index-linked bonds are still based on RPI, as are most inflation-protected pensions and other forms of financial income.

Lastly, Blanchflower demanded that I provide some empirical research that NGDP is less prone to error than RGDP or “inflation”. Well, here is a study by the US statistical office, the Bureau for Economic Analysis that demonstrates that NGDP (“Current-dollar GDP” in the table) is at least as reliable as RGDP looking at the period 1993-2013. This can’t actually be true given RGDP’s two sources of error. The resources spent on RGDP are much larger than those spent on NGDP so that may account for the BEA’s result.

JA-D Blanchflower

Whatever, it at least shows Blanchflower’s “totally impractical” is just wrong in fact as well as theory. He should stop talking nonsense

The great benefit of NGDP Targeting is that it means the central bank concerns itself only with nominal stability and doesn’t have to get concerned with the balance between inflation and real growth, or the hard to measure productivity growth that drives the difference. Those issues can be left to real economy experts to sort out. 

In this way of thinking neither inflation nor Real GDP growth should be of any concern to a Nominal GDP Targeting central bank.

One thought on “NGDP data revisions means targeting it is “totally impractical”, really?

  1. Pingback: Come on George, stand up for NGDP Targeting – NGDP Advisers

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