Sunday, July 15, 2012

Hal R. Varian: How to Build an Economic Model in Your Spare Time


I googled economic model and Hal Varian's PDF (16 pages ) showed up, second on the list.

The first step is to get an idea. This is not all that hard to do. The tricky part is to get a good idea.

I have a good one.

So let's assume (a favorite word of economists) that you have an idea. How do you know if it is any good? The first test is to try to phrase your idea in a way that a non-economist can understand. If you can't do this it's probably not a very good idea. If you can phrase it in a way that a noneconomist can understand, it still may be a lousy idea, but at least there's hope.

Pretty good paper. Funny in spots.

I think I'm pretty good at putting it simply.

Before you start trying to decide whether your idea is correct, you should stop to ask whether it is interesting. If it isn't interesting, no one will care whether it is correct or not.

I'm sure this is correct, and pretty important. I have trouble with it. I thought, if you build it they will come. I thought build a better mousetrap, they'll beat a path to your door. (I didn't really think that but... you know.)

So let's skip the literature part for now and try to get to the modeling. Lucky for you, all economics models look pretty much the same. There are some economic agents. They make choices in order to advance their objectives. The choices have to satisfy various constraints so there's something that adjusts to make all these choices consistent. This basic structure suggests a plan of attack: Who are the people making the choices? What are the constraints they face? How do they interact? What adjusts if the choices aren't mutually consistent?

Asking questions like this can help you to identify the pieces of a model. Once you've got a pretty good idea of what the pieces look like, you can move on to the next stage.

See, here's where I get in trouble. I think Hal Varian is talking about micro models. So I want to ignore this part of his advice. Micro models are never going to solve the macro problem.

I think what Hal describes as a model is really just an explanation. According to him, a model tells who makes the choices, what the constraints are, how they (not sure who) interact, and what adjustments are necessary. Sounds like yadda yadda yakyak to me. Micro yakyak.

I don't think Keynes made Hal Varian-style models in The General Theory. I don't think Adam Smith made Hal Varian-style models in The Wealth of Nations. I think I do things like Smith and Keynes. Ego, I know. So, tell me what you think. But be specific. I don't understand hints.

A model is supposed to reveal the essence of what is going on: your model should be reduced to just those pieces that are required to make it work.

Okay.


On page 10, Varian's theme degenerates into "Planning your paper". It's not a model anymore now, it's just a paper. It goes on for another half a dozen pages and never goes back to being a model.

So, okay. A "model" is not necessarily a computer simulation of the economy or anything involved and complex like that. A model is an explanation.

// Part 2 of 4

Saturday, July 14, 2012

What does one have to do?


Krugman links to Krugman:

If there is a single word that appears most frequently in discussions of the economic problems now afflicting both the US and Europe, that word is surely “debt.”

I doubt that. Krugman continues:

Sharply rising debt, it’s widely argued, set the stage for the crisis, and the overhang of debt continues to act as a drag on recovery.

Not widely enough. Private debt is still largely ignored. Debt is often said to be the same as credit, and credit is thought to be beneficial.

Krugman again:

The current preoccupation with debt harks back to a long tradition in economic analysis, from Fisher’s (1933) theory of debt deflation to Minsky’s (1986) back-in-vogue work on financial instability to Koo’s (2008) concept of balance-sheet recessions.

Yet despite the prominence of debt in popular discussion of our current economic difficulties and the long tradition of invoking debt as a key factor in major economic contractions, there is a surprising lack of models – especially models of monetary and fiscal policy – of economic policy that correspond at all closely to the concerns about debt that dominate practical discourse.

What does one have to do, to construct a "model" that will satisfy some unspecified set of conditions and make economists think it is a "model"? I'm sure I don't know.

I used to avoid using the word "model". But then somebody asked me, How does your model work under such-and-so condition?

Krugman says "there is a surprising lack of models – especially models of monetary and fiscal policy – of economic policy that correspond at all closely to the concerns about debt that dominate practical discourse."

I say there is a contradiction between our assumption that printing money causes inflation, and our assumption that using credit is good for growth. These assumptions lead to a contradiction between monetary and fiscal policy, a contradiction that is the root cause of debt growth.

What more must I do? What kind of model do they want?

Even now, much analysis (including my own [Krugman writes]) is done in terms of representative-agent models, which by definition can’t deal with the consequences of the fact that some people are debtors while others are creditors.

For the record: It does not matter that "some people are debtors while others are creditors." Some are this and some are that as a result of increasing concentration of wealth and income. The fact that some are this and some are that, increasingly, accelerates the growth and increases the severity of the problem. Yes.

But the problem at root is not that some are creditors and some are debtors. That will always be the case.

Nor is the problem at root the increasing concentration of wealth and income. (Later in the cycle of civilization, yes; but not at present. At present we still have the ability to create policies to deal with such things. At present, we lack only the sense to do it.)

The problem is the increasing cost of finance, due to the growth of finance. Financial cost hinders the growth of the productive sector, making financial investment more appealing that productive investment. And that only makes the problem worse.

The increasing concentration of wealth and income is a convenient vehicle by which the increasing cost of finance carries our economy toward an ending from which no recovery is possible.

// Part 1 of 4. More tomorrow.

Friday, July 13, 2012

A Taste of Market Monetarism


"Market Monetarism Blogroll" in the sidebar at Marcus Nunes' Historinhas presents a link to Nick Rowe's What's wrong with New Keynesian macroeconomics -- an MM perspective. Rowe links to Market Monetarism: The Second Monetarist Counter-­revolution, a 36-page PDF by Lars Christensen.

If you've seen the label "market monetarist" and wondered what it means, you might want a peek at that PDF.

This bit of it starts on page 12:
Interest rates are NOT the price of money

A very common fallacy among both economists and laymen is to see interest rates as the price of money. However, Market Monetarists object strongly to this perception. As Scott Sumner spells out in capitals: "INTEREST RATES ARE NOT THE PRICE OF MONEY, THEY ARE THE PRICE OF CREDIT" (Sumner 2011C).

Well, yeah.

On the other hand, the price of money or rather the value of money is defined by what money can buy: goods. Hence, the price of money is the inverse of the price of all other goods -- approximated by the inverse of for example consumer prices.

This is completely in line with the view of traditional monetarists such as Brunner and Meltzer (1997) or Yeager and Greenfield (1986) who strongly stress the difference between money and credit.

Again, yes. Here's how I have it:

The difference between money and credit is that credit is more costly to use. An economy that shifts from a low reliance on credit to a high reliance on credit will find itself with financial costs rising relative to other costs. It will find itself with interest costs rising relative to wages and profits. It will find itself with living standards squeezed, business growth below par, and financial activity as its growth industry.

William Woolsey (2009B), with direct reference to Leland Yeager, spells out the key difference between money and credit.

First, he defines money.

"Money is the medium of exchange. The quantity of money is the amount of money that exists at a point in time. The demand for money is the amount of money that people want to hold at a point in time. To hold money is to not spend it."

Then he defines credit.

"The supply of credit is the amount of funds people want to lend during a period of time. The demand for credit is the amount of funds that people want to borrow during a period of time."

Okay. But the key difference between money and credit is cost.

This cost can be calculated.

Once we distinguish money from credit we want to look at credit in its various phases. For example, what Bill Woolsey calls "the supply of credit" is the same as what I call "credit available". To me, the supply of credit is credit available plus credit-in-use.

The total supply of credit includes both the money available for new lending, and the money already on loan.

There is another difference between my thinking and Woolsey's. See how he sticks the phrase "during a period of time" in there? Twice, he says it. If I had to include time in my definition, I would say "at some moment in time". I see the supply of credit as a stock; Woolsey describes it as a flow. One of us has it wrong.

The first difference is more important. If I decide to borrow a dollar, the demand for credit increases. When I actually borrow a dollar, I put credit to use. Until I repay that debt, the demand for that credit continues to exist. UNTIL I REPAY THE DEBT, THE CREDIT REMAINS IN USE.

The demand for credit is not measured by *new* borrowing alone, but also by the accumulation of existing debt. To ignore credit-in-use is to ignore accumulated debt.

... Woolsey acknowledges that "there are relationships between the supply and demand for money and the supply and demand for credit... But money and credit are not the same thing" and "One of the first rules of monetary economics is to never confuse money and credit."

That's a good rule.

While the Market Monetarists have been calling for quantitative easing to help pull the US out of the Great Recession, they are also critical of the actual implementation of QE under the leadership of Federal Reserve chairman Bernanke. This is because they believe QE in the form implemented by the Federal Reserve focuses excessively on the functioning of the credit markets rather than on expanding the money supply...

That's about right. The Fed is still trying to get people to increase their borrowing, because they still think using credit is always good for growth.

The basic problem is the imbalance between money and credit-in-use or between money and debt, as you can see on my Debt-per-Dollar graph. The focus on increasing credit use rather than on expanding the money supply is exactly the wrong focus.

But the focus on expanding the money supply is also flawed. The problem is not that we have too little money. The problem is that we have too little money relative to accumulated debt. And as you already know, this problem is due more to the growth of private debt than to the suppression of money.

The obvious solution -- the correct solution -- is to reduce private debt.


One more thing: I searched that 36-page PDF for the word debt. Found exactly one occurrence, in footnote 6 on page 3: "While Market Monetarists acknowledge their intellectual debt to Leland Yeager..."

That's the only one.

Thursday, July 12, 2012

On you, Marcus


At Historinhas, Marcus writes:

The chart shows that monetary policy is crucial for macroeconomic stability. During “Keynesianism Rules” (a.k.a. “The Great Inflation”) a rising spending (NGDP) trend initially bolsters real growth (RGDP above trend) a fact that got the 1960s to be called “Golden Age”(!). Soon, most of the rising spending managed only to make inflation roar.

I don't like the name "golden age" either. But Marcus lies. It is not "the 1960s" that's called the golden age. It is the entire post-WWII period, from 1947 until the 1974 recession. Because economic growth was good.

And yeah, it really ended more like in 1967. And yeah, it was the "Great Inflation" -- or, really, it was the thing that caused the great inflation -- that brought the "golden age" to an end. But I'm pointing that out, as opposed to what Marcus is doing: re-defining dates and corrupting concepts in order to make them fit his graph, so he can sell his story.

//

Yeah, I'm gonna call it a lie. Because I like Marcus.

Once more unto the breach


From Ryan Avent via Sumner:

The Fed has the ability to create as much money as it wants and can use that money to purchase every scrap of federal-government debt, every scrap of outstanding mortgage-backed securities backed by federal housing agencies, and as much foreign exchange as other governments will sell it.

Sure. And that would do absolutely nothing to remove debt (payment obligations) from the economy.

The problem is not that we have debt-as-assets (income sources). The problem is that there was so much debt-as-liability (payment obligations) that debt-as-assets became "toxic" (undependable income).

Rather than the Fed printing money and using it to buy up debt-as-assets, they should print money and use it to pay off debt-as-liability. This would destroy the liability and free up the economy to grow again.

The other thing, buying debt-as-assets, puts more money into the hands of people who already have more money than they need, and does nothing about the problem that brought the economy to its knees.

Wednesday, July 11, 2012

QE


Source: CR via JZB

Source: Ebay

Fed Treasury Distributions


From Federal Reserve posted record profit of $78.4 billion last year at the LA Times:


And from Sumner:

And 2011 profits were about the same as 2010 profits. That’s triple the amount Apple earned in 2011. Two hundred billion dollars in 3 years! Folks, that’s a huge, gigantic, vast, enormous, mammoth, tremendous, titanic, humongous, immense, colossal, gargantuan, stupendous amount of money.

Tuesday, July 10, 2012

Oh, my


http://econospeak.blogspot.com/2012/07/yet-again-robert-j-samuelson-proves-he.html

http://www.washingtonpost.com/opinions/robert-samuelson-why-us-economic-policy-is-paralyzed/2012/07/08/gJQARBEwWW_story.html?hpid=z3

http://www.cepr.net/index.php/blogs/beat-the-press/robert-samuelson-blames-the-60s-again

http://krugman.blogs.nytimes.com/2012/07/10/sixties-madness/

Bella and Stella


Sackerson at Broad Oak got my attention with US financial system has now been reset and a graph showing that "For the first time in 40-plus years, the ratio of monetary base to credit in America has returned to 5%."

I felt as if his post was written just for me. I got out five paragraphs of reply before stopping to catch my breath.

The next time I checked my email a copy of my comment was there, plus a comment by Don't have one, linking to The base money confusion by Izabella Kaminska at FT Alphaville.

I jumped right into that.

Kaminska's article combines her own remarks with remarks from Peter Stella, "formerly the head of the Central Banking and Monetary and Foreign Exchange Operations Divisions at the International Monetary Fund."

"He got in touch with FTAV," Kaminska writes,

because of what he feels is a gross misunderstanding in policy and journalistic circles regarding the nature of central bank reserves, and the myth that banks are not lending because they prefer not to.

Stella finds confusion in the idea that

somehow bank reserves at the central bank ought to be “lent out”, i.e. should exit the “vault” of the BOE, Fed or ECB and begin circulating in the economy. The obverse of this is that an increase in excess reserves at the central bank reflects commercial banks “hoarding” liquidity rather than lending it “out”.

He writes:

My frustration lies in my inability to explain to “sophisticated” people why in a modern monetary system–fiat money, floating exchange rate world–there is absolutely no correlation between bank reserves and lending. And, more fundamentally, that banks do not lend “reserves”.

Commercial bank reserves have risen because central banks have injected them into a closed system from which they cannot exit. Whether commercial banks let the reserves they have acquired through QE sit “idle” or lend them out in the interbank market 10,000 times in one day among themselves, the aggregate reserves at the central bank at the end of that day will be the same.

But Mr. Stella ignores differences between excess reserves and required reserves. FRED shows there were essentially *no* excess reserves for half a century, and then suddenly there was a lot of excess.

If lending increased, there might be the same amount of total reserves, but required reserves would increase and excess reserves would fall. It's no mystery, and it should not be overlooked or hidden away or trampled on or left out of the picture.

I have no trouble with the notion that reserves "are not lent out". But reserves have to be kept in reserve, so to speak, when loans are made. Instead of being "excess", some of the reserves switch over and become "required". So, the aggregate reserves at the end of the day will *not* be the same.

Call it a minor point, if you want, but "the same" and "not the same" are not the same.


Kaminska:

As Stella points out, the US banking system could increase lending a thousandfold this year without any change in their deposit holdings at the Fed.

A thousandfold? Possibly. But only because the level of excess reserves is so high.


Kaminska:

The only exception to this is if lending constitutes a sharp rise in physical banknote withdrawals from the system. Or for that matter if commercial banks begin to store reserves in physical banknote form rather than on deposit at the central bank so as to avoid negative charges:

See that? There are exceptions.

Stella:

It is true that banks could reduce their excess deposits at the central bank by exchanging them for physical banknotes and then lend those banknotes out to retail customers.

But "deposits at the central bank" are "reserves". So Peter Stella's claim that "there is absolutely no correlation between bank reserves and lending" must be incorrect.

I need some definitions.

M1 is money in circulation or (as the St. Louis Fed puts it) "funds that are readily accessible for spending." It includes checks and circulating currency. It excludes currency that is not circulating -- currency in bank vaults, basically.

Currency in bank vaults is money in reserve. So are banks' account balances at the Federal Reserve. So: Your cash and your checking account balance count as money in circulation, unless you are a bank. If you are a bank, they count as money in reserve.

When I go to the bank and withdraw $10 from my account, the bank takes the $10 from "the vault" and pays it to me, and then that money is "in circulation". This is the moment the money moves from "in reserve" to "in circulation". It is the moment the money moves from Row 2 to Row 1 and from MB to M1 on this Wikipedia table fragment:


Reserves are money the Fed must pay out on demand, because it is somebody else's money. That's not the same as "open market" operations, where the Fed gets to decide whether or not to buy things. The Fed can choose not to pay out money, if it wants, by deciding not to buy stuff. But it has no choice when it comes to existing reserves.


Kaminska:

As we’ve noted before, bank reserves do not leave the doors of the central bank when credit expands, because one man’s loan is another man’s asset. Every time a bank lends, it actually creates brand new credit. This is done by creating a liability for the borrower on one side, and an asset for itself, which can then be sold on, on the other side. Every increase in credit thus comes with an equivalent increase in savings vehicles. Credit is created with one hand and absorbed by the other hand.

Now there's a jumble of notions.

Kaminska opens the paragraph by pretending to talk about reserves. But then she talks about credit expansion instead. The fact that she fails to show how reserves fit into the picture does not mean they don't have a place in it.

The paragraph sounds like it might be the whole story. It is not. Reserves "do not leave the doors of the central bank when credit expands" because reserves are what must be kept in reserve when credit expands.


A few paragraphs later, Kaminska claims "There is no limit to how much banks can expand credit in this way." But then she follows up:

In systems that carry minimum reserve requirements, base money must at the very minimum cover these required ratios. In these cases, when credit rises base money must also rise or else banks could fail to meet such ratios. However, the central bank almost always provides enough base money to ensure that these ratios are met.

In fact, this is how the central bank enforces policy.

So it seems that reserves and reserve requirements *do* limit how much banks can expand credit. To be sure, the connection is not simple and straightforward. Here's what I was taught: Economic policies in the US are designed not to be coercive.

We induce and encourage, because we have a demand economy, not a command economy. But the fact that our policies work by means of guidance, instead of punitive force, does not mean reserves and reserve requirements serve no purpose. To reiterate Kaminska:

The central bank almost always provides enough base money to ensure that these ratios are met. In fact, this is how the central bank enforces policy.

Almost always, she says. Remember the Volcker squeeze?