It started innocently enough. A friend sent me a link and suggested it would be interesting to do a similar analysis on the velocity of circulation of money for Iceland. This link to be precise:
I’m not an Economist, I’m a Computer Scientist with a rather bizarre hobby - I had to go and look it up.
Something about the idea that the velocity of circulation of money, the number of times each physical note, or bank deposit electron changes hands could affect the price level bothered me, but I couldn’t put my finger on what. I went back to my rather quixotic task of trying to figure out how the banking system actually works. (Step 1, build a computer model, Step 2, discover almost no Economist you talk to about it has a clue how the banking system actually works…)
It stayed at the back of my mind though and continued to bother me. As a Computer Scientist, I specialise in networks and real time systems, so I’d come into Economics originally with a rather vague model of money as packets of information bouncing around and establishing a price level. Did the speed at which they did that really matter? It bothered me, I couldn’t say why, I went and looked it up again.
The original source for this particular version of the Quantity Theory of Money(it turns out there’s several, in and of itself not a good sign), turned out to be a book by an American Economist Irving Fisher written in 1911, called the Purchasing Power of Money:
The thing that immediately struck me about the book was the date. You see, as part of trying to figure out how the banking system works, I’d spent a month going through the 19th Journal of the Statistical Society of London, and a couple of other 19th century Economics Journals I’d found lurking online, and I’d established to my own satisfaction that the earliest that British Economists even appeared to have an inkling about the inately expansionary behaviour of the banking system was 1900 or so, a discovery which was accompanied by a raging debate over whether bank deposits even qualified as money. Money, as far as 19th century Economists were concerned was physical notes and coins.
It’s fairly clear from his book that Fisher was in the bank deposits don’t exactly qualify as money camp.
The quantity theory of money itself, is a simple equation. M (quantity of money) * V (velocity of circulation of money) = P (average price level) * Q(total quantity of production). (If you’re an engineer or a scientist btw., the first thing that’s wrong about that equation is that the units don’t match, but I digress.)
The second problem becomes clear when you look at the example Fisher provides in Chapter 1 section 2, and expand it out a little. Fisher starts with $5 million in money, and total purchases in a year of 200,000,000 loaves of bread, 10,000,000 tons of coal and 30,000,000 yards of cloth, with the prices shown below.
With $5 million in physical cash, it isn’t possible to buy all the coal say at once, which would require $50 million, so a series of exchanges have to occur. $5 million buys 50 million loaves of bread say, the bread makers then buy 1 million tons of coal, the coal miners buy 5 million yards of cloth, and the cloth makers then get to buy some bread. All in all the money circulates around 20 times (which is of course the point), and on the other side of the equation, 20 separate transactions get made with it.
In other words, the velocity of circulation of money can’t affect the price level, because it cancels on both sides of the equation. Oops.
I always wanted to be a scientist. Don’t ask me why, I remember when I was a 9 year old writing an admission essay for the local grammar school, and describing why I wanted to be a scientist. Looking back I have no idea how a nine year old ends up wanting something like that, but I did, and the grammar school gave me a place, which ushered me onto the educational path that at least ends up giving you the training to be a scientist, even if I’ve spent most of my life doing something else. One of the most important things you learn is that extraordinary claims require extraordinary proofs. Questioning the quantity theory of money is right up there on that scale.
Still, I could also see why Fisher needed velocity. Fisher tried in his book to do something quite laudable, he tested his results against actual data. But Fisher didn’t count bank deposits as money, even though British Economists like Dunbar around the same time were pointing out that 90% of all fiancial transactions were being conducted not with notes and coins but cheques. With an unknown expansionary force acting on the total quantity of money, prices were varying in ways Fisher had no way of explaining - and the velocity of circulation of money became a very convenient fudge factor. It still is. The Bank of England uses it to adjust their M4 money supply measure.
Then somethng else dawned on me. When Economists talk about the economy growing, what they mean is that a measurement called the Gross Domestic Product (GDP) is growing. But GDP isn’t the total amount of things produced, it’s the total value of things produced. To get GDP you get the total value of everything that was sold in a year(price * quantity), modify by the inflation rate, and publish widely.
But if you take the quantity theory of money in any way seriously, then that can’t work, because if the total quantity of things produced increases - then the prices will drop. M = P * T’. Fruit is cheap in the autumn. Price is inversely related to quantity. GDP can only increase if either production decreases (causing price increases due to shortages), or the money supply increases. That of course, is why GDP ‘works’ - the money supply in most countries is more or less continuously increasing, and study the banking system for any length of time, and you will develop a rough feel for which countries have the fastest expanding money supplies. A quick check confirmed, they also had high GDP’s.
A friend of mine heroically volunteered to plough through a bunch of Central Bank sites and pull out the relevant money supply and GDP data. A bit of jiggerypokery with matplotlib, and we had a paper showing what happens to GDP if you normalise it to correct for the growth in the money supply. (In the majority of countries it’s slowly shrinking, probably because money is getting pulled into the financial sector.) GDP it seems isn’t measuring economic growth at all - it’s just measuring the growth in the money supply.
Well, that’s what scientists do. They write papers, and try to get other people to read them (this it turns out is the really hard part.) With one honourable exception, none of the economists who so far admit to having read the paper understood what it meant to normalise data. [If you know that the tape measure you’re measuring with has magically doubled in length, you can still use it to measure if you halve all the measurements you make.] My fellow engineers get it immediately, they’re just not sure that that’s really how GDP is being measured.
Once friends and colleagues have been exposed to it, the next step for any paper is to try and get it into a conference or journal. So far the paper’s been rejected by two conferences and 2 journals. Without any response at all as to why.
In my own field that wouldn’t happen. Question one of the central tennets of computer science, and have the timerity to submit it to a conference, and you can expect to get either a detailed description of your own stupidity, or an invitation to explain further. But as I’d already learned with the Banking System, this is Economics, they do things differently over there.
So that’s science. Looking at a problem, and trying to figure out if you’re completely wrong, or if everybody else is, and with mild humiliation as the most likely outcome. Papering the wall with rejection emails. Some peer review would be nice. In the meantime I’m building a computer model, it seems as good a way to explore the problem as any. A really simple economy with just a few employees, a farm, and a market to set prices. Something I can play around with, and try and figure out the math. So far it’s not looking good for GDP. It’s not looking good for the rest of the equation as it happens, but it’s too early to be sure.
There’s something about it all though. Reading economics papers and realising that almost none of them normalise for the money supply growth. Looking at a computer model, a few figures updating, trying to work out if its behaviour is a bug, or a real feature of the monetary system. Caught on the edge of knowledge and belief as the results begin to match the hypothesis. Knowing, if nothing else, that that nine year old was totally right about wanting to be scientist.