Links and happenings

Busy times for yours truly over the last two weeks. Here is a list of things that I've been doing, plus one or two items that I spotted on ye olde internet.

1) I moved apartments! More or less the same size as our old place, but more comfortable and modern. Here is a little photo taken from the (car-free) route that I cycle to school everyday. Not too shabby, eh?

2) I had the pleasure of acting as moderator for the inaugural TEDxBergen conference. (My school has actually been hosting TEDx events for a while, but they've now expanded to include the other educational institutions in the city.) The speakers were all very interesting, with two or three in particular being excellent. I believe the video(s) for the event will be made available shortly, so I'll link to them then.

3) I gave a lecture on shale gas (and fracking) to the master's class in Petroleum Economics this week. My slides are here!

4) On a more prestigious note, two Nobel laureates recently gave lectures at my school. (i) As I pointed out on Twitter, Chris Sims is sounding an awful lot like an MMTer /Post-Keynesian lately. (ii) Finn Kydland makes a provocative claim that we are more resilient to energy price hikes today than we were in the past. His argument is that the adverse economic effects of the 1970s' oil shocks largely manifested themselves as inefficient tax rises due to the monetary and fiscal systems of the time. This in turn caused investment and employment to fall. I'm entirely not sure about this story -- the declining energy intensity of our economies would seem to play a bigger role -- but it's an interesting idea.

5) As predicted, some people are using the terrible events at the Westgate Shopping Mall in Nairobi to disparage "interventionist" foreign policy. I'm not saying that they don't have a point -- although, the ongoing anarchy in Somalia is certainly destabilising to the area and has negatively affected Kenya's economy. I'm saying that if blowback is the measure by which policy is to judged, then consistency dictates that one should make equally narrow arguments against (say) liberal immigration policy, subsidy revocation or economic austerity. What's sauce for the goose, is sauce for the gander after all.

6) To my American friends that have to suffer through the asinine politicking of the Republican party and the twilight-zone-thought-vacuum of Fox News, you have my sympathies.

Inflation-targeting, CPI measures and the poor

In a bid to get back to regular blogging, below is a comment that I've just left under a Daily Maverick column by Paul Berkowitz, entitled "Who benefits from inflation-targeting?" It includes the following provocative graph on the relative inflation levels faced by different consumer groups in South Africa.

___

There are a number of legitimate reasons to critique an inflation-targeting regime. Further, the relatively high inflation burden felt by poorer segments of society certainly merits attention in of itself. That said, there are some persistent misconceptions among the public about inflation-targeting: What are its goals and what are the (theoretical) mechanisms by which these are achieved -- particularly w.r.t. a central bank's chosen CPI measure? My gripe with this article is that it may perpetuate such misconceptions by failing to acknowledge an important principle of inflation-targeting.

Rather than simply being an end in of itself, an inflation target is also seen as a means of stabilising the output gap (and ultimately smoothing of the business cycle). Theoretical justification for this so-call "divine coincidence" -- which implies no trade-off between the twin goals of stabilising inflation and maintaining optimal economic output -- is derived from the standard new Keynesian DSGE models favoured by a large segment of macroeconomists. See Blanchard and Gali (2005), or as Blanchard has written elsewhere:

This is a really important result. It implies that central banks should indeed focus just on inflation, and can sleep well at night. If they succeed in stabilizing inflation, they will automatically generate the optimal level of activity. (p. 3)

The upshot is that, if we are going to criticize the representativeness of headline CPI for all income groups, then we should at least acknowledge it's (intended) wider role in stabilising the output gap. (The CPI basket is chosen, after all, because it corresponds to average purchases within the economy as a whole.) You can certainly argue about the conditions under which "the divine coincidence" is satisfied, as well the theoretical underpinnings of the DSGE models. However, closing the output gap is probably very much in the poor's interest as well.

On a final and related note, there are severe drawbacks to the SARB targeting a predominantly commodities-based basket that would more closely accord with the average purchases of low-income families. Most obviously, the SARB is more or less powerless to control the inherent volatility of commodity groups, not to mention the potential for causing very counterproductive amplifications in the consumption cycle. (See here, esp. end of point 4.)

Are there any four-minute miles in economics?

3:59.4

Roger Bannister's four laps of the Iffley Road Track on 6 May 1954 have been immortalised in the annals of sporting lore and human achievement. By becoming the first man to run a sub-four minute mile, he had broken the "impossible" barrier and so made clear the importance of mind over matter. Athletes from all over the world would soon replicate Bannister's feat now that he had liberated them from their mental shackles...

Except... no. The problem with this romantic narrative is that it has been hopelessly embellished. The idea of a four-minute "barrier" was almost entirely the invention of the media, which fanned the idea to sell papers as runners increasingly closed in on the mark. Wikipedia (indulge me) puts it quite nicely:

The claim that a 4-minute mile was once thought to be impossible by informed observers was and is a widely propagated myth created by sportswriters and debunked by Bannister himself in his memoir, The Four Minute Mile (1955). The reason the myth took hold was that four minutes was a nice round number which was slightly better (1.4 seconds) than the world record for nine years, longer than it probably otherwise would have been because of the effect of World War II in interrupting athletic progress in the combatant countries.

I was reminded of this yesterday, as my Twitter and Facebook feeds were flooded by excitable and angry complaints about the Dollar-Rand exchange rate breaching the symbolic threshold of 1:10.

Source: Bloomberg

Now, to be sure, the Rand is at it's weakest level for several years following a number of social upheavals, government scandals and political infighting, questionable economic policy, and wider trends in emerging markets. (Here, here and here for more context.) I should also say that I am not endorsing a "weak Rand" strategy here in any shape or form. I am, however, interested in the question of whether a 1:10 exchange ratio is significant in of itself.

Put differently, do we have reason to believe that the Rand's rate of depreciation will accelerate further as a result of having passed this threshold? I must confess that I don't see it. That's not to say that further depreciation can't happen, but rather: a) That would be the result of existing economic fundamentals rather than surpassing some magic metric mark, b) A full-blown currency crisis seems very unlikely from my perspective. (If nothing else, the South African Reserve Bank is on record as saying that they will tighten policy in the advent of further weakening, although that remains very open to interpretation.)

Moving beyond the case of the USD-ZAR exchange rate, the notion of thresholds pervades much of economics and finance... Or, at least, it pervades talk about economics and finance. Consider, for example, some of the headlines from recent weeks concerning the fall of gold prices to below $1,500 and then $1,400 per ounce... or the brouhaha surrounding that Rogoff-Reinhart paper and their fabled elusive "90 percent" cut-off rate for debt-to-GDP ratios and its supposedly dire consequences on economic growth.

Some of this -- let's call it -- threshold affinity in economics and finance could be justified by underlying factors, such as physical laws, regulatory limits, etc. However, most of it is probably just good copy for selling financial news. At worst, it may even be self-referential nonsense designed to confuse lay investors and the general public. Here are two stylised explanations for why "round number" thresholds shouldn't matter in of themselves:

1. Valuations should ultimately be set according to economic fundamentals. These would not be much different for a stock or trade that is valued at, say, R9.90 versus R10.10.
2. An alternative reason is that traders don't target levels per se. Rather, they target the levels implied by momentum and trend lines (with predefined margins of safety), or algorithmic strategies (which are similar in principle). There's no a priori reason to think that these implied levels will accord to nice round numbers.

Having said that, market psychology can obviously work very differently to the cool, rational calculations implied by standard theory. "Round numbers" will become important, as long as enough people believe them to be important. More precisely, symbolic levels will gain significance if I believe that other people regard them as being significant. (Ye old beauty contest story.) It should also be said that even standard theory does not suppose that change should evolve in a linear fashion...

Let me end this post by saying that I haven't bothered with any kind of literature research; I'd be interested in hearing about studies investigating this type of phenomena. Alternatively, if not much has been done and someone is interested in looking at it further... drop me a line. Two possibilities for checking the existence of "four-minute mile" numbers is that they should act as focal points or thresholds. For the former, we would expect data to bunch around particular levels from both above and below. For the latter, we would expect a discontinuity in the rate of change for a particular stock or currency valuation (i.e. once a threshold is breached). Several ways of testing this empirically immediately spring to mind.

Monetary regimes and economic outcomes

Eric Rauchway has a post over at Crooked Timber that's generating a fair bit of interest, since it compares real economic growth and inflation for the "G7" countries over various monetary regimes.

His data is taken from a 1993 paper by Michael Bordo and consequently doesn't cover information from the last two decades. ("I made you some charts. Because I love you that much. (But not enough to extend the floating exchange rate regime data down to the present; that’s actual work.)")

Well, that sounds like a challenge. And if anyone is fit to do mind-numbing compilation of data[*], that would be your typical economic graduate student...

Behold: I give you Rauchway's charts brought forward to the present day!

Fig. 1

Fig. 2

Compared to Rauchway's charts, the updated versions bring both good and bad changes from the perspective of floating (fiat) currency proponents. On the positive side, inflation has come down quite a bit. On the negative side, so has real GDP growth -- although to a lesser extent. You can better see this by looking at the next two charts, which compare the 1974-1989 (i.e. as in Bordo's paper) and 1990-2011/12 periods of the post-Bretton Woods era.

Fig. 3

Fig. 4

Of course, this is more or less as one would have guessed. We know that late '70s and early '80s were a period of high inflation -- with various shocks and loose monetary policy to blame. On the GDP side, it's interesting to note that Japan appears to be the primary driver of slower growth in the latter part of the post-Bretton Woods era (Fig. 3). Given that it's stalling economy is probably suffering from a lack of monetary accommodation to drag it out of liquidity trap conditions -- Note: recent events may provide the decisive policy experiment to prove whether this is the case or not -- it's far from obvious to me that the strictures imposed by the alternative monetary regimes would have yielded better outcomes. (I've had my say at various times on this blog as to why I think returning to a gold standard is a rotten idea, so I won't go into that now.)

And, on that note, I should say that I fully agree with the various commentators in the Crooked Timber thread, who have been pointing out that these don't charts don't nearly suffice i.t.o. counterfactuals, etc, etc. Still, these eyeball comparisons remain an intriguing bit of blogosphere fun. 

___

[*] It actually wasn't that much work thanks to our friendly FRED friends.

More on inflation, violence and identification

Chris has responded to my previous post, which he frames as a criticism of his research. I should state upfront that this does not strike me as entirely accurate, since I emphasized at various points that my concerns lay in the possible journalistic interpretation of his work. Some email correspondence between the two of us suggests that I am not alone in expressing such trepidations, but I digress. On then, to Chris’s response…

1) He begins by taking issue with my decision to focus on food prices, politely suggesting that I “may have missed” the fact that his non-discretionary index of living costs includes various other components (including rent, electricity, water, etc).

As it happens, I don’t think that I missed this at all. My reasons for focusing on food prices are quite simple. First, they provide relevant context to the real effects that I highlight in my post, i.e. agricultural shocks stemming from massive drought. This was done deliberately with the aim of illustrating the overriding message of my post: Attributing causation to any particular event is often very difficult, and we certainly have to bear real effects in the front of our minds when discussing the sources of inflation. (To reiterate, this is something that the Business Day article failed to do entirely.) Second, food prices provide an obvious segue to the other article that I discuss in my post, which concerns the role that monetary expansion had in driving up food prices and thus precipitating the Arab Spring. Such matters notwithstanding, however, I did happen to include the following passage in my original post:

To be clear, South Africans have also experienced sharp increases in the cost of amenities like electricity and water provision due to some boneheaded policy decisions and as a legacy of inefficient parastatal monopolies.

Chris may have missed that, though. (wink)

2) His second objection is that I am unfairly interpreting his research as a suggestion that food hikes are the only cause of violence. He quotes his references to “political grievances” as evidence that I haven’t read the article properly.

Again, however, this seems to be a misunderstanding of what I have written and the major point of my post. In the passage that he quotes, I'm not concerned with alternative causes of violence, but rather the underlying drivers of one particular cause, i.e. inflation. At the risk of repeating myself: To the extent that inflation does act as a trigger for social unrest and violence – and irrespective of whether that occurs alongside other factors such as political grievances or not – we need to understand what the underlying forces behind that inflation are. Any analysis that focuses only on the nominal effects of (quote unquote) “delinquent” monetary policy is simply misleading. Why? Well, because there may be very significant real price drivers occurring at the same time! This is something that the Business Day article completely failed to mention, and the same is true for The Telegraph article that I quoted in the second half of my post. I see nothing wrong with taking exception to such slipshod analysis.

3) Next issue: On my suggestion that one might baulk at the definitive description of this research as “proof” of the relationship between inflation and violence...  Well, I don’t have much to add here, since – again – this is a criticism of how the journalist chose to frame his article. “Proof” is simply too strong and simplistic a word to use given all this issues that I have raised. (Note: I see that this has happened elsewhere.)

4) The penultimate point that Chris makes in his reply extends beyond the article featured in Business Day.  I will summarize his argument as saying that the South African Reserve Bank (SARB) should abandon its focus on the headline CPI, because a) Non-discretionary inflation has been rising much faster, b) It cannot control which specific goods rise and fall in price, and c) It would better facilitate an environment of civil harmony by stabilizing the Rand against a basket of commodities.

Now, interestingly enough, subsequent to yesterday’s post I found this column that Chris has penned himself. (I’ll take it that we can safely assume away possibility of incorrect interpretation by a third party here.) He produces the below graph and proceeds to write: 

Seeing as Non-Discretionary goods price inflation has averaged well above the SARB’s price inflation target of 6% for most of the past seven years, low income groups’ standards of living are falling at a compounded rate relative to high income earners. [Emphasis mine.]

I don’t have the raw data to hand, but eye-balling the chart it doesn't seem at all obvious to me that non-discretionary goods have “averaged well above” the 6% inflation target. (Does it seem obvious to anyone else?) In fact, I’d hazard a guess that it averages a shade below the 6% mark. Certainly, the strongest statement that we can probably make about this series is that it fluctuates around that general level.

We all agree that no single measure of price changes is perfect. Indeed, it is precisely for this reason that we have constructed so many different indices in the hopes of getting a better sense of how “inflation” is playing out in the economy. Central banks like the SARB choose to follow a preferred metric – like the CPI – for a number of reasons, most of them very sensible. As it happens, the sheer volatility of commodities is a key reason why some CBs prefer “core” to “headline” inflation measures. Trying to conduct monetary policy in response to a simple basket of commodity prices would not only be incredibly difficult due to the inherent volatility (and the fact that the CB is more or less powerless to  stop these short-run swings), but potentially counterproductive because of the amplifying effect that it could have on consumption cycles. (For more discussion, see Matt Rognlie’s excellent posts on this subject: here, here, and here.)

5) As for his final point, that peer review is not superior to insights that bring in paying clients… Well, clearly that is not what I meant by “cracking” the problems of identifying a causal link between price increases and the uprisings in the Arab world. (Mind you, if he did accurately predict these events in advance of them happening then I certainly am impressed.) So, while I regard the profit mechanism as essential as the next economist, that has nothing to do with my concerns about getting to grips with some very obvious identification problems. That said, allow me to make a broader concluding remark: Just as no-one should suggest that peer-review is infallible, we should never confuse profitability with validity. Even psychics have been doing a roaring trade for centuries. It doesn't make them right.

Is gold highly correlated with money supply?

Amidst all this talk about US Republicans eyeing a return to the gold standard, something on my twitter feed earlier this week caught the eye: A link to an old Zero Hedge post together with a claim that "there is a 93% correlation between M2 [money supply] and gold". A similar post here is more specific in saying "[t]he correlation between the total U.S. M2 and gold has exceeded 0.90 since November 2004".

Now presumably, this tweet was aimed at countering the inconvenient fact that the correlation between price inflation (i.e. CPI) and gold is virtually zero. And, if predictions of imminent hyperinflation have yet to materialise, well then at least "hard money" types can point to way in which monetary inflation has manifesting itself in the surging gold price of the last decade. (There's a lesson to be learned here about the velocity of money, kids, but that will have to wait until another time...)

Anyway here's a graph of the gold price and U.S. M2 since 2004, taken from the FRED website. Both are shown in terms of moving monthly averages and, sure enough, the correlation looks very high indeed.



Unfortunately, there are two things wrong with this picture. The first is that the time-frame really does matter. The second has to do with the statistical properties of these series. Let's take these two issues in turn.

Consider what happens when we look at the period from 1981 (which is first date for which FRED has data on both series) until 2004.



Woah! That positive relationship isn't looking too good all of a sudden. Now, of course, I can already hear angry golden-tinged voices accusing me of dueling a strawman. The correlation coefficient was specifically cited for the 2004-post period, so who really cares about what happened 20 or 30 years ago? Okay, perhaps something special happened around the mid-2000s that explains why the two variables have since become so intertwined. Fine, but then don't try to tell me that it's anything specifically to do with money supply. The noticeable kink in the M2 series leading up to that moment occurs around 1995 (after a period of mild tapering), which is close on a decade before the supposed special relationship with gold prices begins.

The broader point here is that if you are going posit a structural theory for why two variables are related, then that relationship needs to have enduring qualities. If not, how can you be sure that gold and M2, rather than one causing the other, aren't both being driven by some other factor? (For one thing, the money supply is supposed to be endogenous to what is happening in the broader economy...) I'm inclined to argue that focusing on the period since 2004 is just a form of data-mining and, as we'll see next, not a particularly good example of that anyway.

Okay. So, ignore the fact that the (weak) longer-term correlation between M2 and gold prices matters. Surely, eight years of data showing a 90%+ correlation can't be denied? Surely, we can say with extreme confidence that recent gold prices have been greatly influenced by money supply? Right?

RIGHT??

Sadly, no. Whenever someone points excitedly to very high correlations between trending time-series, your spidey-sense should be going off like Peter Parker on methylamphetamine. The reason lies with one of the fundamental concepts in time-series econometrics: Nonstationarity.

Wait a minute. Are those series... nonstationary?

Without getting too bogged down by statistical concepts, nonstationary series are characterized by a mean and variance that are changing over time. It's not that they can't be growing or declining over time, but rather that they should consistently return to some kind of mean trend. The most important thing from our perspective is failing to account for this issue will generally lead to spurious (i.e. "nonsense") regression results; an idea that goes all the way back to a classic paper by Yule  in 1926.

Aaaaaaaand.... as you might have guessed by now, the above series are nonstationary. In technical parlance, they are referred to as random walks with drift. Now, there is a famous exception to this rule that occurs when two series are said to be "cointegrated". Again, I'd rather avoid delving too deeply into the murky waters of statistics in a blog post, but suffice to say that that cointegration does not hold here.

To avoid the problems of bullshit spurious regressions, we must therefore adopt a tried and tested approach: Take the first differences of the series and only then test for correlation. Doing so produces a correlation coefficient of exactly <drum roll>... 0.32. Moreover, if we actually regress gold on M2 we get a pretty unimpressive R-squared statistic of 0.1. In other words, only ten percent of the gold's movements are explained by what is happening to money supply.  [UPDATE: Based on the comments, let me again emphasise that these numbers are specifically for the "highly" correlated post-2004 period.]

THOUGHT FOR THE DAY: Simply regressing gold prices on any nonstationary series -- whether that be iPhone sales or the number of Crocs™ wearers in Bangladesh -- would likely produce equally impressive, but obviously bogus, results. Now gold fans might be inclined to protest loudly at this point: "Duh", but there's no theoretical basis for linking those goods to gold. We have a theory that predicts the price of gold will rise with (monetary) inflation!" Except that we've just tested that theory and found it, if not entirely wanting, then at least highly oversold. Perhaps a bit like gold then... [See comments.]

PS - For anyone interested in checking all of this for themselves, here is some Stata code that I used to test the series. The code will always call the most recently available FRED data, so the exact figures you get may differ from those presented here depending on when you run it.

NOTE: In writing this post, I see that others have effectively made the same point before.

Privileging theory over evidence

It's late and my brain is in desperate need of sleep, but I've just read something very interesting on the Mises.org blog (via Twitter). In particular, Bob Murphy shapes to provide a takedown of a new book by economic anthropologist, David Graeber, on the true origins of money: Debt: The First 5,000 Years. Bob's motivation appears to stem, in large part, from the awkwardness that Graeber's thesis would imply for adherents of Austrian economics. As he writes in the introduction to his article:

Last week the popular blog "naked capitalism" ran an interview with David Graeber, an "economic anthropologist" whose new book allegedly destroys the standard account of the origin of money. If correct, Graeber's views would prove embarrassing to the Austrian School, because it was none other than Carl Menger who developed the first systematic explanation for how people went from barter to a full-blown monetary economy.

Bob then goes on to summarise Menger's position, before refuting Graeber's challenge in the body of his post... Which is all good and well, except that Graeber has provided an outstanding reply in the comments section, which rather eviscerates the original critique.

Graeber's comment is very long (broken up into six parts), but well worth reading through the whole thing to get a full sense of his arguments. In the interest of being fair to any Austrian readers, at this point I should probably say that -- as suggested by the quoted text above -- this is more a matter of pride than a fundamental attack on, say, ABCT. While awkward for Austrian sympathisers, I'm not trying to claim that the possibly of Menger being wrong in this instance serves to invalidate the edifice of Austrian Theory...[*]

That being said, it remains a very interesting topic, especially in these fractious times where the proponents of "hard money" and fiat currency are clawing at each other's throats. More fundamentally, the debate serves to highlight something closer to my own heart: The dangers of privileging theory above evidence.

As Graeber's writes:

As for the supposed refutation of my example of the village where people loan things to one another, no, [Murphy] does not get my argument right at all. First of all, we are not dealing with a situation where people borrow things from one another and expect an equivalent of exactly the same value. I suppose the certain Austrian school theories of human nature assume that's what neighbors in a moneyless economy would do with one another, but again, this just shows a flaw in those theories of human nature, because when tested against the empirical evidence, this is not what one finds.[...]  

[snip] 

I think the participants in this forum should reflect on what they consider the status of economics to be. Is it a science that generates hypotheses about empirical reality that can then be tested against the evidence, and changed or abandoned if they don’t prove to predict what’s empirically there? Or is it a kind of faith, a revealed Truth embodied in the words of great prophets (such as Van[sic] Mises) who must, by definition be correct, and whose theories must be defended whatever empirical reality throws at them – even to the extent of generating imaginary unknown periods of history where something like what was originally described “must have” taken place? 

Well said. I've expressed my scepticism about the extreme a priori approach adopted by certain Austrians before (e.g. here and here). Yes, it's true that we can deduce much about human behaviour and economic systems based on a few key assumptions -- indeed, all theory aims to do something along those lines. However, I find the notion that these simple axioms provide the foundation for understanding the full complexity of economic activity, without the need for supporting empirical evidence to be... well, nothing short of the pretence of knowledge.

[*] Indeed, from my reading of things, Graeber appears to be refuting Adam Smith's account of the barter economy as much as anyone. Let me also state for the record that I actually look forward to Bob's response. I've seen him stage a comeback before after appearing completely cornered on an issue before, so you never know...