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Glenn Stevens is not quite God

Alan Kohler has a piece on Crikey talking about electricity prices in Australia.  It’s an interesting piece and well worth a read, but it’s got a crucial economics mistake.  After talking about the politics and such, Alan gets down to brass tacks, telling us that:

  • Over the last two years, electricity prices in Australia have risen by 48% on average; and
  • Indeed, over the last five years, electricity prices have risen by more than 80% on average; but
  • Over the last twelve months, overall inflation has only been 1.5%, the lowest in three years.

He finishes by explaining:

That’s because the increase in power prices has been almost entirely offset by the high Australian dollar, which has produced tradeable goods deflation of 1.4% over the past year. In other words, thanks to the high Australian dollar we are getting a big improvement in energy infrastructure without an overall drop in living standards.

And thank goodness for fast rising power prices — without that, we’d have deflation. It’s true!

But it’s not true, and it’s not true for a very important reason.

Back in 1997, in the guts of of the Great Moderation (the time from the mid ’80s to the start of 2007 when US aggregate volatility was low) and before the real estate boom that presaged the financial crisis of 2007/2008, Paul Krugman famously wrote (this Economist piece is the best reference I could find in the two minutes I spent looking on Google) that unemployment was whatever Alan Greenspan wanted it to be, “plus or minus a random error reflecting the fact that he is not quite God.”

It’s popular to argue that Ben Bernanke lacks that power now that America has interest rates at zero. I disagree (see here and here), but I appreciate the argument.

Australia has no such problem. Interest rates are still strictly positive and the RBA has plenty of room to lower them if they wish.

So I have no qualms at all in saying that inflation in Australia is whatever Glenn Stevens (the governor of the RBA) wants it to be, plus or minus a random error to reflect the fact that he’s not quite God.

If the various state grids had all been upgraded a decade ago and electricity prices were currently stable, then interest rates would currently be lower too. They would be lower because that would ensure faster growth in general and a lower exchange rate, both of which would lead to higher inflation, thereby offsetting the lower inflation in electricity prices.

There’s a famous argument in economics called the Lucas Critique, named for the man that came up with it, that points out simply that if you change your policy, economic agents will change their actions in response.  It applies in reverse, too, though.  If economic agents change their actions, policy will change!

Alan Kohler ought to know this. Indeed, I suspect that Alan Kohler does know this, but it’s a slippery concept to keep at the front of your mind all the time and, besides, it would make it hard to write exciting opinion pieces. 🙂

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Defending the EMH

Tim Harford has gone in to bat for the Efficient Market Hypothesis (EMH).  As Tim says, somebody has to.

Sort-of-officially, there are three versions of the EMH:

  • The strong version says that the market-determined price is always “correct”, fully reflecting all public and private information available to everybody, everywhere.
  • The semi-strong version says that the price incorporates all public information, past and present, but that inside information or innovative analysis may produce a valuation that differs from that price.
  • The weak version says that the price incorporates, at the least, all public information revealed in the past, so that looking at past information cannot allow you to predict the future price.

I would add a fourth version:

  • A very-weak version, saying that even if the future path of prices is somewhat predictable from past and present public information, you can’t beat the market on average without some sort of private advantage such as inside information or sufficient size as to allow market-moving trades.

    For example, you might be able to see that there’s a bubble and reasonably predict that prices will fall, but that doesn’t create an opportunity for market-beating profits on average, because you cannot know how long it will be before the bubble bursts and, to regurgitate John M. Keynes, the market can remain irrational longer than you can remain solvent.

I think that almost every economist and financial analyst under the sun would agree that the strong version is not true, or very rarely true.  There’s some evidence for the semi-strong or weak versions in some markets, at least most of the time, although behavioural finance has pretty clearly shown how they can fail.  The very-weak version, I contend, is probably close to always true for any sufficiently liquid market.

But looking for concrete evidence one way or another, while crucially important, is not the end of it.  There are, more broadly, the questions of (a) how closely each version of the EMH approximates reality; and (b) how costly a deviation of reality from the EMH would be for somebody using the EMH as their guide.

The answer to (a) is that the deviation of reality from the EMH can be economically significant over short time frames (up to days) for the weak forms of the EMH and over extremely long time frames (up to years) for the strong versions.

The answer to (b), however, depends on who is doing the asking and which version of the EMH is relevant for them.  For retail investors (i.e. you and me, for whom the appropriate form is the very-weak version) and indeed, for most businesses, the answer to (b) is “not really much at all”.  This is why Tim Harford finishes his piece with this:

I remain convinced that the efficient markets hypothesis should be a lodestar for ordinary investors. It suggests the following strategy: choose a range of shares or low-cost index trackers and invest in them gradually without trying to be too clever.

For regulators of the Too-Big-To-Fail financial players, of course, the answer to (b) is “the cost increases exponentially with the deviation”.

The failure of regulators, therefore, was a combination of treating the answer to (a) for the weak versions as applying to the strong versions as well; and of acting as though the answer to (b) was the same for everybody.  Tim quotes Matthew Bishop — co-author with Michael Green of “The Road from Ruin” and New York Bureau Chief of The Economist — as arguing that this failure helped fuel the financial crisis for three reasons:

First, it seduced Alan Greenspan into believing either that bubbles never happened, or that if they did there was no hope that the Federal Reserve could spot them and intervene. Second, the EMH motivated “mark-to-market” accounting rules, which put banks in an impossible situation when prices for their assets evaporated. Third, the EMH encouraged the view that executives could not manipulate the share prices of their companies, so it was perfectly reasonable to use stock options for executive pay.

I agree with all of those, but remain wary about stepping away from mark-to-market.