“Milton Friedman Knew This”

Brad DeLong is frustrated. People arguing that government spending displaces private consumption and investment on a one-to-one basis don’t seem to realize that their argument rests on the (indefensible) presumption of a constant money multiplier and a constant velocity of money:

Time to Bang My Head Against the Wall Some More (Pre-Elementary Monetary Economics Department), by Brad Delong: Oh boy. John Cochrane does not know something that David Hume did–that the velocity of monetary circulation is an economic variable rather than a technological constant. Cochrane:

Fiscal Fallacies: First, if money is not going to be printed, it has to come from somewhere. If the government borrows a dollar from you, that is a dollar that you do not spend, or that you do not lend to a company to spend on new investment. Every dollar of increased government spending must correspond to one less dollar of private spending.  Jobs created by stimulus spending are offset by jobs lost from the decline in private spending. We can build roads instead of factories, but fiscal stimulus can’t help us to build more of both. This is just accounting, and does not need a complex argument about “crowding out”…

Let us take this slowly.

Suppose that we have four agents: Alice, Beverly, Carol, and Deborah.

Suppose that Beverly has $500 in cash that she owes Carol, due in two months. Suppose that Alice and Carol are both unemployed and idle.

In one scenario in two months Beverly goes to Carol and pays her the $500. End of story.

In a second scenario Beverly says to Alice: “I have a house. Why don’t you build a deck–I will pay you $500 after the work is done. Here is the contract.” Alice takes the contract and goes to Carol. She shows the contract to Carol and says: “See. I will be good for the debt. Cook me meals so I will have the strength to build the deck–here’s another contract in which I promise to pay you $500 within 90 days if you cook for me.” Carol agrees.

Two months pass. Carol cooks and feeds Alice. Alice goes and builds the deck.

Alice then asks Beverly for payment. Beverly says: “Wait a minute.” She goes to Carol and says: “Here is the the $500 cash I owe you.” Beverly pays the money to Carol. Beverly then says: “But now could I borrow the cash back by offering you a long-term mortgage at an attractive interest rate secured with an interest in my newly more-valuable house?” Carol says: “Sure.” Beverly files an amended deed showing Carol’s mortgage lien with the town office. Carol gives Beverly back the $500. Beverly then goes to Alice and pays her the $500. Alice then goes to Carol and pays her the $500.

The net result? (a) Alice who would otherwise have been idle has been employed–has traded her labor for meals. (b) Carol who would otherwise have been idle has been employed–has traded her labor for a secured lien on Beverly’s house. (c) Beverly has taken out a mortgage on her house and in exchange has gotten a deck built. (d) Carol has the $500 cash that Beverly owed her in the first place.

Alice has more income and consumption expenditure than if she hadn’t taken Beverly’s job offer. Carol has more income and saving than if she hadn’t cooked for Alice and then invested her earnings with Beverly. Beverly has an extra capital asset (the deck) and an extra financial liability (the mortgage) than if she had never offered to hire Alice.

A deck has gotten built. Meals have been cooked and eaten. Two women have been employed. And all this has happened without printing any extra money.

John Cochrane would say that this is impossible. John Cochrane would say:

[I]f money is not going to be printed, it has to come from somewhere. If Beverly borrows a dollar from Carol, that is a dollar that Carol does not spend, or does not lend to Deborah to spend on new investment. Every dollar of increased Beverly spending must correspond to one less dollar of Carol or Deborah spending.  Alice’s job created by Beverly spending is offset by a job lost from the decline in Carol or Deborah spending. We can build decks instead of fountains, but Beverly stimulus can’t help us to build more of both. This is just accounting, and does not need a complex argument about “crowding out”…

John Cochrane is wrong.

You sometimes see this mistake in freshmen students in Economics 1, students who do not fully understand either the circular flow of economic activity or what a credit economy is. They think–like Cochrane–that the flow of spending must be constant unless somebody “prints money” because, you see, you need “money” in order to buy things.

The premise is true–you do need “money” to buy things–but the conclusion is false: the flow of spending is not necessarily constant. In the world in which Beverly does not hire Alice but instead pays the $500 directly to Carol, that $500 turns over only once–its velocity of circulation is equal to one. In the world in which Beverly does hire Alice, the velocity of circulation of the $500 is four–it goes from Beverly to Carol, from Carol to Beverly, from Beverly to Alice, and from Alice to Carol.

Cochrane’s mistake–an elementary, freshman mistake–is because he has not thought enough about how a credit economy works to recognize that the velocity of circulation can be an economic variable and is not necessarily a technological constant. And as the velocity of circulation varies, the amount of the flow of spending varies as well: it is now longer the case that if Beverly borrows a dollar from Carol that is a dollar that Carol does not spend.

Milton Friedman knew this. Irving Fisher knew this. Simon Newcomb knew this. David Hume knew this. John Cochrane does not know this: does not know that the velocity of circulation is an economic variable rather than a technological constant.

I do want to pound my head against the wall.

I do not know what else to do…

pgl has more. Arnold Kling calls Cochrane’s essay, generously, “muddled.”


Originally published at the Economist’s View reproduced here with the author’s permission.

One Response to "“Milton Friedman Knew This”"

  1. Guest   February 13, 2009 at 6:38 am

    good point, what is happening right now is that banks’ troubles have stopped the flow of spending at a time where people have increased their propensity to save. Banks’ current assets are partially wothless as a consequence of past leverage and self-indeptment, and they are increasing liabilities (deposits) without buying new assets. We are assisting to destruction of money supply. In such a situation, government spending is using resources which the system won’t put into use anyway.