The monetary transmission mechanism

The reason that New Keynesians don't like talking about the supply of money and velocity has nothing to do with problems in defining the supply of money, the instability of velocity, or the instability of the money supply multiplier. As I argued in my last two posts, similar criticisms would apply equally to the New Keynesians' actual and natural rates of interest.

The real reason is the New Keynesian view of the monetary policy transmission mechanism. They see it as working through interest rates. Given sticky prices, an exogenous decrease in the supply of money causes interest rates to rise which causes aggregate demand to fall, which causes a recession. So why not just cut out the irrelevant cr*p about money, and just say the central bank raises interest rates which causes aggregate demand to fall? Money and velocity play no role in the story. You can talk about them if you like, but they don't help you understand what's going on, and are merely a distraction.

New Keynesians have this precisely backward. Interest rates are neither necessary nor sufficient for the monetary policy transmission mechanism. Money/velocity is both necessary and sufficient.


Assume sticky prices.

Lets break this into two parts.

1. To show that interest rates are not necessary in the transmission mechanism, imagine a world with no interest rates at all. The only asset is money, which pays 0% interest. It's a backscratching economy, where backscratches must be paid for with money. Or Paul Krugman's baby-sitting coop, if you like. [Don't want to search for the link and blow my monthly ration of NYT views. Update: thanks to Phil, here's a Slate link.] Start in equilibrium. Then part of the stock of money is destroyed. At the existing PY, actual velocity exceeds desired (actual M is less than desired). So individuals buy fewer backscratches to reduce their actual velocity (to try to rebuild their actual money stocks). There's a recession, even though there are no interest rates. We can explain the recession in terms of money and/or velocity. Money/velocity is sufficient to explain the recession, while interest rates are not necessary.

Or, imagine a world in which there are non-money assets, but the interest rates on those assets (or their prices) are fixed by law, so cannot change. Start in equilibrium. Then part of the stock of money is destroyed. So individuals try to sell bonds and land etc. to rebuild their money stocks. But they fail to sell bonds and land, because everyone is trying to do the same thing, and prices of bonds and land cannot fall, so there's an excess supply. So they buy fewer backscratches instead, and there's a recession, even though interest rates never changed.

2. To show that interest rates are not sufficient in the transmission mechanism, imagine a world with barter rather than monetary exchange. The central bank controls not the supply of money but the supply of bling. Bling is the medium of account (prices are measured in terms of bling), but there is no medium of exchange. Bling does not circulate. We can't meaningfully talk about the velocity of bling. Because wearing bling is a form of conspicuous consumption of a durable good, and a way of flaunting ones real wealth, there is a demand for real bling, M/P, which depends positively on real income Y and negatively on the nominal interest rate (the opportunity cost of wearing bling). M/P = L(Y,i).

Suppose the central bank reduces the supply of bling. Interest rates rise, as people try to sell bonds and land to buy more bling. Since prices are measured in terms of bling, and prices are sticky, the real stock of bling M/P cannot rise back to equilibrium.

Does the increase in interest rates cause a recession due to deficient aggregate demand? "What do you mean we are both involuntarily unemployed because of deficient aggregate demand? This is a barter economy. Here's the deal: I scratch your back and you scratch mine. That way we are both better off, and we both get back to full employment." No, there is no recession, despite the central bank's tight bling policy causing high interest rates.

OK. Interest rates may play a role in the monetary policy transmission mechanism. For one thing, the demand for money (desired velocity) depends on interest rates. But the interest rate channel is just one way of telling the story of the transmission mechanism. It is not essential. It is neither necessary nor sufficient.

120 comments

  1. Scott Sumner's avatar
    Scott Sumner · · Reply

    Joe, You said;
    “When you say, “I’d prefer to say the HPE was anticipated by the markets.” Wouldn’t it be more accurate to say “Future HPE was anticipated by the markets…. and created a current HPE all on its own…. which went through all the asset markets.” Expectations go up, money demand falls, HPE happens through the asset markets, price in asset markets go up. Right?”
    If I understand you correctly, that is right. I was thinking of the HPE from the future increased money supply, but you’re right that it also occurs from the current lower money demand.
    I don’t follow your other point about supply and demand not changing. Expectations of the future are one of the most powerful determinants of current supply and demand, especially in asset markets. So if the expected future price rises, the current demand rises and the current supply falls, leaving prices higher and quantities unchanged in the very short run.

  2. Kevin Donoghue's avatar
    Kevin Donoghue · · Reply

    Scott: “…there must be a REASON why a monetary increase causes prices to rise in a flexible price model.”
    The reason is simply that there is a new equilibrium price level. That’s all there is to it. At the old price level, there would be an excess supply of money and an excess demand for goods. That’s disequilibrium and we can’t have that. So the auctioneer stops the clock, like a referee waiting for an injured player to be taken off the football pitch. Time is suspended while the new price is determined. No trading whatever takes place at any price between the old equilibrium and the new.
    Is your HPE just a folksy term for disequilibrium? If so you are just wrong to say that Keynesians (Old or New) ignore it. Recall Friedman’s remark that Keynes reversed the classical assumption: “Changes in output (aggregate supply), not in prices, play the major role in producing equilibrium.” So your hot potato is there all right, it’s just not so unbearably hot that we are desperate to get it off our hands. As Friedman clearly implies, prices play a minor role in the adjustment process, but they do play a role. We wait patiently until our firm’s number comes up on Calvo’s fruit-machine and then we change our price.
    You know all this obviously, so it’s really quite hard to see what you’re getting at. In some peculiar way you seem to have convinced yourself that Keynesians have a model in their minds which is not the model they have actually written down. Not so. WYSIWYG.

  3. Adam P's avatar

    I’m not sure I can really add anything to what Kevin just said but I’ll go ahead and put it in my own words anyway…
    The point is that in the fully flexible price model there never is a hot potato effect. To see why let’s see where the hot potato effect was supposed to come from, let’s normalize the demand for real balances to equal 1. Suppose that the money supply M = 100, then in equilibrium it must be the case that the price level P = 100. Thus M/P = 1 and we are in equilibrium.
    Now, suppose M changes to 200. The hot potato effect is supposed to result from the fact that now aggregate real balances M/P = 2 which is more than demanded and so the desire to get rid of the excess causes the hot potato.
    BUT…
    with flexible prices P immediately jumps to 200, as Scott has insisted, so there is never any time for which M/P fails to equal 1, hence no hot potato effect.
    Now, as Kevin points out, apparently Scott has in mind that the expectation that an HPE would happen out of equilibrium is what enforces the equilibrium. However, in the off equilibrium situation where people have excess real balances the interest rate would also change, unless Scott has some reason why the HPE effect happens in all markets except the bond market. Neither effect has greater claim to be the transmission mechanism.
    Now, in the real world how do we know that it’s not an excess demand for cash balances that caused the recession?
    WE KNOW FROM DIRECT OBSERVATION THAT THE DEMAND FOR MONEY DID NOT INCREASE!
    We know this because the price of treasury bonds went up, if agents in aggregate wanted more money they absolutely could have had it by selling their bonds for cash.
    But, isn’t it the case that we can’t ALL sell our other assets for cash at the same time because the money supply is fixed? NO. The federal reserve maintains an interest rate target as it’s policy instrument, if there was ever a shortage of cash then this would have put upward pressure on the fed funds rate as banks tried to borrow cash to settle their client trades. The fed would have had to respond by increasing the money supply to keep the rate from rising.
    If excess demand for the medium of exchange is the problem then why aren’t bond prices higher?

  4. Kevin Donoghue's avatar
    Kevin Donoghue · · Reply

    Adam, I was with you until your last sentence. I guess you mean why aren’t bond prices lower, and bond yields higher. What we actually observe is what Brad DeLong keeps banging on about: excess demand for safe assets.

  5. Philo's avatar

    When Scott Sumner says that “99% of monetary transactions are for assets unrelated to NGDP,” is he referring to trading in financial assets? There are also black-market/criminal transactions, and gifts; perhaps I’m missing some other categories. Still, 99% seems kind of high.

  6. Adam P's avatar

    kevin, yes I meant why aren’t bond prices lower?
    and I was agreeing with DeLong.

  7. Patrick's avatar
    Patrick · · Reply

    Scott: I’m not an economist, and I stay away from these theoretical arguments because I have nothing to add. So I’m not arguing anything or taking any position at all – just trying to follow the argument.
    Everything I’ve read about AD/AS is always in real terms and Y = f(M/P, …). Based on text book AD/AS as read by a rank amateur, I’m confused by your assertion that simultaneous and proportional increases in M and P would affect Y. I’m not saying you’re wrong, I’m just saying I’m not following. If you can explain, fine. If you’re not inclined to or think I’m too dumb to get it, fine. But I’m not arguing.
    On German hyperinflation: Again, I’m not following you. How is that relevant? By definition, wouldn’t one expect real balances to crash in a hyperinflation? AFAIK, M/P doesn’t say anything about the dynamics and expectations that create the hyper-inflationary conditions in the first place.
    Anyway, I’m probably just too out of my element here so I’ll leave it at that.

  8. Philo's avatar

    On second thought, I suppose a lot of monetary transactions are sales of second-hand items. Sales of labor, services, and newly produced goods contribute to NGDP, sales of second-hand (not “newly produced”) goods are non-NGDP transactions. 99% is beginning to sound less unreasonable, though still dubious.

  9. Determinant's avatar
    Determinant · · Reply

    Further to RSJ’s post on how the Bank of Canada implements its interest rate policy, the market used is the Large Value Transfer System, the wire-based collateralized clearing system in Canada. Cheques and other personal items are cleared through the ACSS, where the interest rates are 1.5% above LVTS rates by BoC policy.
    LVTS is a deferred net settlement system, it is balanced once per day and transactions are covered by pledged securities in a common pool (Tranche 2) or Bank of Canada deposits (Tranche 1).
    LVTS and the corridor are designed so that banks settle their balances among themselves before turning to the Bank of Canada. The corridor is designed so that when the overnight rate gets outside it there is an instant arbitrage opportunity to force it back inside the bank.

  10. Unknown's avatar

    Wow. Comments have been flowing well here. I’m just back from a few days holiday, giving the MX6 some exercise — driving to London via Orillia. My head’s still not up to speed yet.
    Adam: “Can someone please explain to me why the fed buys bonds, usually t-bills, when it wants to ease?
    Why not open a savings account at all the biggest banks, when you want to expand the money supply make a deposit, when you want to contract the money supply make a withdrawal.
    The fed deposits could be lent out on fed funds market or to fund, say, mortgages. No need to hold assets in order to sell them when you want to drain reserves back out.
    Why isn’t it done this way?”
    Up until a couple of decades ago, that is very much like how the Bank of Canada did control the money supply. They called it “drawdowns and redeposits”. It was always a PITA to teach, because I always got it muddled which was which. But it went like this:
    The Government of Canada had a chequing account at the Bank of Canada and also at the commercial banks (BMO, TD, etc.). The BoC managed the government’s chequing accounts. It it wanted to ease, the BoC would transfer the government’s funds out of its BoC account into its accounts at the commercial banks. If it wanted to tighten, it would transfer the government’s funds the other way.
    It used these “drawdowns and redeposits” for fine-tuning monetary policy, and open market operations for gross tuning.
    I think (if my brain is working) that is effectively the same as what Adam is talking about. (It was a demand deposit, rather than a savings account, but as Adam says later, that is an inessential detail of his question).
    Why did the BoC stop doing it this way?
    Good question. I don’t know. But I don’t think there was any fundamental reason why it was unworkable. Just unnecessarily complex?
    Moreover, today the BoC sets a target for the overnight rate, but to actually keep the actual overnight rate as close as possible to that target, the BoC adds or withdraws settlement balances on an hourly/daily basis for “fine tuning”. How is that fundamentally different from the old “drawdowns and redeposits” mechanism, or what Adam is talking about?
    I should have a sleep, then return to this thread.

  11. Determinant's avatar
    Determinant · · Reply

    Probably when LVTS was introduced. There is a book in pdf form on the Bank of Canada’s website which details the evolution of the payments and clearing system in Canada by Canadian Payments Association. The Bank of Canada re-evaluated and changed its Overnight policy implementation mechanism when LVTS went online. LVTS handles something like 80% of the value of the money transfers daily in this country including several large transfers from the federal government to the provinces, according to that book.

  12. Adam P's avatar

    “The Government of Canada had a chequing account at the Bank of Canada and also at the commercial banks (BMO, TD, etc.). The BoC managed the government’s chequing accounts. It it wanted to ease, the BoC would transfer the government’s funds out of its BoC account into its accounts at the commercial banks. If it wanted to tighten, it would transfer the government’s funds the other way.”
    That is exactly what I was talking about. So they used to do this and apparently stopped, RSJ thought this was an idiotic thing to do so perhaps that explains why they stopped.

  13. RSJ's avatar

    Nick,
    I think what you are talking about is something different — it sounds like the TT&L accounts in the U.S., which is a way for the (Federal) government to coordinate with the CB to prevent excess OMOs from being required when taxes are paid. You can think of the government as having an account with the CB, and when it collects taxes, that is a reserve drain, as funds are transferred from banks to the CB. This would force the CB to do a reserve add in order to prevent an overall system reserve deficiency. One way around this would be for the government (not the CB) to move some funds out of its account with the CB and into a commercial banking account, keeping the reserves available to the banks.
    And the reason why this would be stopped would be that the government (not the CB) can get more for its money via a competitive auction, rather than just depositing it. Nevertheless, you still see a version of this today, although I would not call it monetary policy. It is done by the government, not the CB.

  14. Unknown's avatar

    RSJ: “I think what you are talking about is something different — it sounds like the TT&L accounts in the U.S., which is a way for the (Federal) government to coordinate with the CB to prevent excess OMOs from being required when taxes are paid.”
    No. IIRC, that is what the BoC does now. Nowadays, it uses the same drawdowns and redeposits mechanism, but in a purely passive way, to offset day-to-day (month-to-month?) fluctuations in government spending and receipts, and prevent these causing fluctuations in the money supply/overnight rate.
    But, in the olden days (20 years ago?) it also did this actively, to deliberately cause a change in the money supply, and not just to offset those fluctuations in government spending and receipts.
    IIRC, Determinant is right about the active use of drawdowns and redeposit mechanism ending when the LVTS came in. And we Canadian teachers of ECON1000 all breathed a sigh of relief and deleted a couple of paragraphs from the textbooks, our lecture notes, and our brains.
    Here is the way my very abstract over-simplifying brain thinks about the whole thing:
    If the BoC wants to increase the money supply, it buys something. It doesn’t really matter (much) what it buys. It could be a bicycle, a computer, forex, or an IOU — the effect on the money supply is the same. The BoC gets a bicycle to add to its assets, and the seller of the bicycle gets the BoC liability (“cash”). But the BoC buys no bicycles, few computers, rarely (nowadays) forex, and mostly buys IOUs. But what sort of IOUs (whose signature is on the IOU?)? And does it buy those IOUs directly from the entitity that signed those IOUs, or indirectly on the market? For gross-tuning, the BoC buys IOUs signed by the government of Canada, but not directly from the Government. We call this “open market operations.” For fine tuning, the BoC buys IOUs signed by the commercial banks. What Adam is talking about is buying a commercial bank IOU directly from the Bank. And that IOU is redeemable on demand. It’s essentially a chequing account.
    There’s some technical reason why the BoC no longer does what Adam is talking about. Maybe because it made JKH’s old job (at the commercial banks) a hassle.

  15. Unknown's avatar

    RSJ: “So the reason why the interest rate management is the only transmission mechanism is because that is how our institutions are set up. If you change the institutions — and there is no outside money or banks in your model — then the transmission mechanism will be different.”
    [You are using “inside” and “outside” money in the exact opposite ways those words have traditionally been used in economics.]
    An institution is a set of beliefs about other players’ reactions to your actions. It has no concrete reality aside from those beliefs. The “gold standard” was one such set of beliefs. The current “target 2% inflation by an adjustable overnight rate target” is another set of beliefs. What you call “how our institutions are set up” is not something separate from our beliefs about the transmission mechanism. The Bank of Canada’s current operating “mechanism” is a reification of the Bank of Canada’s theory of the monetary transmission mechanism. Anybody who says “the BoC sets an interest rate” has simply swallowed the BoC’s theory of the transmission mechanism whole, in the same way that someone who describes missionaries as “spreading the word of God”.

  16. Unknown's avatar

    James Hudson’s comment, reproduced in full:
    “”Given sticky prices, an exogenous decrease in the supply of money causes interest rates to rise which causes aggregate demand to fall . . . .” This is too compressed to enable me (a non-economist) to understand the New Keynesian view. I think “aggregate demand” is just spending (or is it spending on consumer goods?), in which case a fall in the quantity of money would itself reduce AD (assuming no corresponding increase in velocity). So money supply looks intrinsically relevant to AD. But how are interest rates supposed to be relevant? If I am a debtor, continually rolling over short-term debt, a rise in interest rates will (very likely) reduce my contribution to AD; but if I am a creditor, continually receiving interest payments, won’t a rise in interest rates increase my contribution to AD, perhaps by an offsetting amount?
    So I understand (or, at least, think I understand) the monetarist picture, but the New Keynesian model remains completely unintuitive. Though this may run against the grain, could you please do a bit more to make the NK picture plausible?”
    NR here:
    [AD is just demand for spending on newly-produced goods and services – consumption plus investment goods. And in a world where sellers nearly always sell you what you demand to buy (they don’t tell you to wait or join the queue), demand for spending nearly always equals actual spending.]
    Now Jame’s comment is interesting because, as a non-economist, he has not been “indoctrinated” into the ‘official’ view of the monetary transmission mechanism. So he can’t ‘see’ how a cut in interest rates is supposed to increases AD.
    A cut in r makes debtors better off and creditors worse off. But yes James, those offsetting effects on AD (the “income effects”) should roughly cancel (and are usually assumed to cancel in NK models).
    Here’s how a monetarist would answer James’ question: “The fall in r is not what causes AD to increase. The fall in r is simply a possible side-effect of the increased supply of money, because people may try to lend out some of the excess money, rather than spend it themselves. Moreover, that fall in r, because it reduces the opportunity cost of holding money (if the rate of interest on holding money stays the same) simply reduces velocity and actually means that the increase in Ms causes a smaller increase in AD than it otherwise would.”
    Here’s the ‘official’ answer: “Forget money. People have a choice between holding bonds and buying goods. A fall in r makes holding bonds less attractive, so people buy more goods instead”.
    But can we forget money? We use money, not bonds, to buy goods.

  17. Unknown's avatar

    RSJ: “The important point is that what matter is the marginal cost of reserves, not the quantity of reserves. This is basically the dispute here. Nick focuses on quantity, and needs some God-given assumption about the relationship between quantity and marginal cost. He should be focusing on the marginal cost of money rather than the quantity of money.”
    How exactly does the BoC keep the actual overnight rate more or less exactly at the mid-point of the 50bp operating band between the interest rate on reserves and the deposit rate? Why doesn’t the actual overnight rate fluctuate over that 50bp range all the time?
    If you ask people at the BoC this question, they will talk about quantity. If the actual overnight rate is above the target midpoint, the BoC increases the quantity of settlement balances in LVTS, so the excess hot potato causes the overnight rate to fall, and when it has fallen to the midpoint the BoC removes the hot potato. If it’s below the mid-point, the BoC removes settlement balances (maybe even making them negative?), and the shortage of musical chairs causes the overnight rate to rise, and when it has risen to the midpoint the BoC replaces the chair.
    The above is almost exactly how I have heard BoC people describe it.

  18. Unknown's avatar

    Patrick (on Scott): “Everything I’ve read about AD/AS is always in real terms and Y = f(M/P, …).”
    Most economists talk about AD in real terms — Yd. I prefer to talk about AD this way.
    But some economists (including Scott) prefer to talk about AD in nominal terms — PYd.
    Neither is right or wrong. I will skip a long argument on the relative advantages and disadvantages of each. (Or whether AD should mean the whole AD curve instead.). But yes, it can be confusing.

  19. Unknown's avatar

    Kevin and Adam: Here’s Adam “The point is that in the fully flexible price model there never is a hot potato effect.”
    We would never observe a hot potato effect in real time. But that doesn’t mean it doesn’t exist.
    Let me give an analogy (stolen from Michael Parkin).
    Q. Why is Lake Erie exactly the same height on the Canadian and US sides of the border? Why don’t (say) boats have to climb a 1 metre high wall of water when they cross the border to the US?
    A. Suppose there were a 1 metre high wall. Then the pressure on the US side would be higher from the extra height and weight of water. Then water would flow from the US side to the Canadian side of Lake Erie, which would equalise the heights of water.
    Scott is saying that if P did not instantly double, then there would be a hot potato effect, and this explains why P does instantly double.
    This all harks back to Patinkin’s distinction between the equilibrium experiment and the stability experiment.
    We still need to invoke the stability experiment in order to explain why the current state of affairs is an equilibrium, and what maintains it in being.

  20. Kevin Donoghue's avatar
    Kevin Donoghue · · Reply

    Nick, I’ve no idea how you find the time for all these responses. I couldn’t and I don’t even have a job. Your comments on the hot potato effect tend to confirm that I’m reading Scott correctly. His hot potato is just disequilibrium. Which is fine, but that means that practically every model I’ve ever seen incorporates the hot potato effect. You could say it’s missing from the original fixprice IS/LM model, but that’s strictly a short-run model. I’ve never met anyone who was misled by it into thinking that the price level will stay fixed when demand gets a significant boost.

  21. Adam P's avatar

    “But can we forget money? We use money, not bonds, to buy goods.”
    Speak for yourself mate, I almost always use a bond.

  22. Scott Sumner's avatar
    Scott Sumner · · Reply

    Kevin, I’m confused by your response. Are you saying the interest rate mechanism drives prices higher, but the money supply/demand equilibrium explains the new long run (higher) price level? That makes no sense to me.
    Adam and Kevin, Regarding the HPE, see Nick’s example with Lake Erie, it’s an excellent analogy.
    Adam, The demand for money certainly did increase sharply in 2008-09, and it’s not even a matter of dispute. We have very precise data on the supply and demand for base money, and the demand soared in late 2008, indeed it more than doubled. So I have no idea why you can claim that it didn’t. Perhaps your interest rate theory suggests it didn’t but then your interest rate theory must be wrong, and demand for base money more than doubled, even in real terms. The public’s demand for of real cash balances is more the double the level of 2007, if you define cash as the base. But other aggregates also increased substantially.
    Friedman pointed out that ultra-low interest rates are a sign money has been tight. In a forward-looking model it is very possible that tight money reduces yields on Treasury securities. In December 2007 a contractionary Fed policy surprise reduced bond yields from 3 months to 30 years. Keynesians can’t explain that, because they have the wrong model. They focus on interest rates, which is the price of credit, not the price of money.
    Philo, I was not intentionally exaggerating. I believe the forex market alone is more than 100 times GDP.
    Nick, Those comments were very helpful, but I’m still confused. Let’s say AD is not the curve, but rather the real quantity demanded. Then:
    1. I’ve been teaching it wrong all along. I tell my students that in the classical model the AS curve is vertical, and thus an increase in AD will lead to nothing more than higher prices. But I should be saying the classical economists didn’t believe AD could be increased.
    2. Or perhaps that’s wrong also. What if there is a huge population inflow, lots more consumers. I taught my students that this would not directly increase AD, rather it would directly increase AS. But if we care about the real quantity of purchases, then more immigration would reduce prices and increase real AD. Ditto for a productivity spurt. So now I’m hopelessly confused. If AD isn’t nominal spending, how do we teach the AS/AD diagram? How do we explain that the slope of the SRAS curve determines how much of the extra AD leads to higher prices, and how much leads to higher output?
    3. Until his most recent edition, Mishkin said one interpretation of AD is a rectangular hyperbola, i.e. a given NGDP. Then he dropped it from the new edition. Did someone tell him it was wrong?
    4. I’m pretty sure I’m not the only economist teaching students that a rightward shift in the AD curve is an increase in AD. I’d be curious how many teach it that way.

  23. Kevin Donoghue's avatar
    Kevin Donoghue · · Reply

    Scott: “Are you saying the interest rate mechanism drives prices higher, but the money supply/demand equilibrium explains the new long run (higher) price level? That makes no sense to me.”
    No, I’m not saying that. To avoid misunderstanding, let’s stick to ‘the’ New Keynesian model. (I’m more comfortable with Old Keynesian models but it’s high time I caght up.) I’m assuming that the simple version I know, from Gali’s textbook, is typical. If it’s not then hopefully Adam or Nick will set the record straight.
    In each period some firms, selected at random, are permitted to reset their prices. The proportion of firms who get permission can be 100%, so there you have a flexible-price version of the model. If there is an unexpected easing of monetary policy all firms raise their prices. Output is always at the optimal, ‘natural’ level. Money is neutral. The only mechanism at work here is good old-fashioned profit maximization.
    If only 30% of firms get permission to change prices in each period then the easing of policy will generate a positive output gap (actual output > ‘natural’ output). That 30% of firms will increase their prices. It’s exactly the same mechanism; it just isn’t allowed to work as freely as in the flexible-price case.

  24. Adam P's avatar

    Scott, usually the term “increase in demand” implies an upward shift in the demand curve. That is, after all, how you used the term with respect to AD above.
    In the case of money during the crises, while the quantity of money held increased, its price plummeted (the price of holding money is the opportunity cost, the nominal rate).
    When quantity increases but price falls it is the supply that has increased, not the demad. The supply curve has shifted and the price fell as we moved along the demand curve. The price fall was what made agents willing to hold the extra supply.
    It would be highly unusual for anyone to call this an increase in demand for money.

  25. Determinant's avatar
    Determinant · · Reply

    How exactly does the BoC keep the actual overnight rate more or less exactly at the mid-point of the 50bp operating band between the interest rate on reserves and the deposit rate? Why doesn’t the actual overnight rate fluctuate over that 50bp range all the time?
    I thought that was a result of the normal function of traders and fund managers in the overnight market doing their thing in a classic micro way. The payments book certainly leans that way. From what I understand the Canadian overnight market operates in a Lombard fashion, where overnight balances are settled among the clearing banks themselves before turning to the Bank of Canada.

  26. JP Koning's avatar
    JP Koning · · Reply

    With regards to the Bank of Canada’s management of government deposits. Even though the old drawdowns and redeposits mechanism is no longer, the BoC still manages government deposits through twice daily competitive auctions. Banks bid for these funds. These are called “Receiver General Cash Balance Auctions”, or something along those lines.
    The government usually keeps very small balances ($1 billion?) at the BoC. ie most of its balances are auctioned by the receiver general. That changed during the credit crisis – the government held at its peak around $25 billion at the BoC. So if the credit crisis is any indication, cash management is not an entirely passive instrument. For some reason the BoC chose not to auction of those funds.
    This is all pretty similar to TTL accounts down south.
    Before LTVS, these deposits were allocated. They are now auctioned.

  27. Adam P's avatar

    “1. I’ve been teaching it wrong all along. I tell my students that in the classical model the AS curve is vertical, and thus an increase in AD will lead to nothing more than higher prices. But I should be saying the classical economists didn’t believe AD could be increased.”
    That effectively is what classical econmists, meaning RBC types, think. They don’t even think AD is a well defined concept.

  28. Adam P's avatar

    As I understand it, in large part the original point behind monopolostic competition and sticky prices was to write down a properly specified model in which AD makes sense as a concept.

  29. RSJ's avatar

    “How exactly does the BoC keep the actual overnight rate more or less exactly at the mid-point of the 50bp operating band between the interest rate on reserves and the deposit rate? Why doesn’t the actual overnight rate fluctuate over that 50bp range all the time?
    If you ask people at the BoC this question, they will talk about quantity. If the actual overnight rate is above the target midpoint, the BoC increases the quantity of settlement balances in LVTS, ”
    No. By being ready to lend in unlimited amounts at rate x+ .5%, and by paying interest on reserves equal to x%, the bank keeps the marginal cost of reserves at x + .25%.
    The Central Bank controls price, not quantity.
    Moreover, the central bank, in our institutional setup, has no quantity control over currency + deposits.The non-financial sector is easily able to obtain more money, in aggregate, simply by selling some of their bonds to the financial sector. The non-financial sector is easily able to get rid of their deposits by buying bonds from the financial sector.
    The money supply, for the non-financial sector, is 100% endogenous. All the central bank can do is alter the short rate, and hope that this causes the non-financial sector to want to hold more or less money, in which case more or less money will be automatically supplied by the financial sector.
    This is what I mean about needing to get the institutions right.
    Moreover, it makes a very big difference what the central bank buys. If the CB buys consumption goods, it is generating income for someone in the economy — that is fiscal policy, and central banks cannot do this.
    If they could — if they could hire unemployed labor or buy up excess inventory, for example, then they really would be able to get us out of a liquidity trap with fiscal policy.
    But they can only purchase assets, which does not increase anyone’s savings. Fiscal policy is an income operation, whereas monetary policy is a balance sheet operation that leaves savings unchanged. Again, the only (indirect) mechanism of the central bank to increase savings is to try to adjust the short rate and hope for capital gains.

  30. Unknown's avatar

    RSJ: “No. By being ready to lend in unlimited amounts at rate x+ .5%, and by paying interest on reserves equal to x%, the bank keeps the marginal cost of reserves at x + .25%.
    The Central Bank controls price, not quantity.”
    Stop and think.
    If I am willing to sell an unlimited quantity of apples at $125; and am willing to buy an unlimited quantity of apples at $75, this will not ensure that the price of apples will be exactly $100 at all times. All it ensures is that the the price will not be less than $75 or more than $125.
    And if you look at the data, you will see that the actual overnight rate is almost never exactly in the middle of the band. But it is far closer to the middle than we would expect if all the BoC did was set those upper and lower bounds. It doesn’t wander around all over the place within those bounds, and rarely hits those bounds (last couple of years at the ZLB aside, when the BoC wanted it to).
    For example: http://www.bankofcanada.ca/rates/interest-rates/canadian-interest-rates/
    At 11.45 am each day, the BoC does repos, or reverse repos, if the actual rate is above or below the target. That’s how it gets the overnight rate almost exactly to the middle of the band.
    More here on how it all works: http://www.bankofcanada.ca/wp-content/uploads/2010/07/lvtsmp3.pdf

  31. Unknown's avatar

    Scott: “1,2,3,4”
    With one small exception, you are not doing it wrong, in my opinion.
    Leave that small exception aside, for a minute.
    In micro, if we are being careful, we make a distinction between “demand” (the demand curve relating P and Qd) and quantity demanded (real Qd). We ought to do the same in macro. But we are sloppy, and most of us use the same words “AD” for both.
    Why are we sloppy?
    1. Because “Aggregate quantity demanded” sounds a bit of a mouthful, so we use “AD” instead.
    2. Because, if aggregate quantity demanded is on the horizontal axis, we often argue among ourselves about what should be on the vertical axis (P or r?) of the AD curve, and often want to slide over potential disagreements by fudging this issue.
    3. Because, the AD curve (whether P or r is on the vertical axis) isn’t strictly a demand curve, in the pure micro sense. It’s strictly a semi-equilibrium condition. That’s because Yd is itself (usually) a function of Y. So what we call an AD curve is a locus of points in {Y,P} space such that Y=Yd(P,Y).
    4. Because we are innately sloppy.
    Everything makes sense if we just adopt the Principle of Charity and interpret “AD” to mean either “Yd” or “the AD curve” according to whichever interpretation means the speaker is talking most sense.
    The small exception:
    In general, depending on the model, the exact parameter values, and what you are assuming constant when you draw the AD curve, it will not be an exact rectangular hyperbola. An exogenous change in AS will only leave P.Yd constant in a very special case.
    The AD curve will have one shape under the gold standard, another if M is fixed, another if the nominal exchange rate is fixed, etc.
    If you assume “monetary policy” is fixed when you draw the AD curve, and by “monetary policy” you mean “PYd”, then you get a rectangular hyperbola AD curve by assumption. But if you held the price of gold fixed instead, you would almost certainly get a different-shaped AD curve.
    This, Scott, is where your normative preference for monetary policy to level-target NGDP has over-ridden your positive theory of the shape of the AD curve. It’s hard for you to see an AD curve that has a different shape from the one you think it “ought” to have. As an antidote, ask yourself what the shape of the AD curve would be if the Fed targeted the price level. It would be horizontal.

  32. Unknown's avatar

    Adam: “As I understand it, in large part the original point behind monopolostic competition and sticky prices was to write down a properly specified model in which AD makes sense as a concept.”
    I think I have heard others express the same view. It’s an interesting viewpoint, but I think I disagree with it.
    (And, as the person who first introduced monopolistic comp into macro, I have some authority on this subject ;-).)
    What the monopolistic revolution did do is find a way to relate AD to the demand curve facing an individual firm. Under perfect competition, you could say that aggregate Yd was 100 apples, but if 10 firms wanted to sell 12 apples each, you had no coherent way of describing the demand curve facing an individual firm. Strictly, the Qd for an individual firm was 100 apples if the firm priced a fraction under every other firm, 0 apples if it charged a fraction more, and an indeterminate quantity between 0 and 100 if it charged exactly the same price as the other firms. That ugly “non-function” got replaced by a nice smooth demand function when we switched to monopolistic competition. So now you could talk sensibly about the costs and benefits to the individual firm of changing its price.
    That was important. And a really good thing. And I expect you could say that it helped us understand AD better, because we could now relate it to the firm’s micro demand curve.
    But it’s not the same as making sense of AD as a concept. I actually think the NK revolution has caused us to go backwards there. Mostly because we have ignored other stuff that got crowded out by the insights of monopolistic comp.

  33. Unknown's avatar

    Scott: “We have very precise data on the supply and demand for base money, and the demand soared in late 2008, indeed it more than doubled.”
    I’m going to side with Adam here. We don’t have data on Md or Ms. We only have data on M. ?

  34. RSJ's avatar

    Nick,
    It would be in the middle because money is not an apple — e.g. it is not a consumption good.
    If one bank is in a surplus position, another bank is in a deficit by the same amount.
    The surplus bank can lend to the deficit bank at a rate Y, or it can leave its funds overnight with BoC, getting target – 25 bp. The bank in deficit can borrow from the BoC, paying target + 25, or it can borrow from the surplus bank at the rate Y.
    The Nash Equilibrium rate will be Y = target — which is why the rate is usually in the middle.
    So while it’s true that at 11:45, the BoC has the contingency option of using SRA or SPRAs, since the first four years since LVTS system was formally implemented, SPRAs were used only 3.4% of the time, and SRAs were used only 0.21% of the time. As each SPRA is unrolled the next business day, that means that at least 96% days, nothing happened at 11:45, as the Nash equilibrium was the actual equilibrium, up to an acceptable margin.
    Of course the theoretical equilibrium does not have to be the actual equilibrium price, so it’s good to have a fallback with OMO, but that is all they are — rarely used fallbacks when the ideal results don’t hold.
    //www.bankofcanada.ca/wp-content/uploads/2010/02/wp06-15.pdf

  35. Unknown's avatar

    RSJ: Interesting find. Sounds as though in 2001 the BoC switched from using 11.45am repos to maintaining a positive (but adjustable) early morning Cash Setting Target?

  36. Scott Sumner's avatar
    Scott Sumner · · Reply

    Kevin, I’m fine with that explanation, but still don’t see where you need interest rates to play a role in the transmission mechanism. You could imagine an economy with just cash and goods, no interest rates. Goods prices are sticky, 30% adjust each period. OMOs are done with some good, like gold. I’m arguing that the monetarist HPE does the job in that economy, and that expectations of it occurring also do part of the (short run) job in an economy that does have interest rates, and all of the long run job.
    Adam, We must be defining money demand differently. To me the price of money is 1/P. That’s exactly the same definition we use in microeconomics for the price of any other good or service. And the price of money went up in 2009 (deflation) and has been pretty stable over the entire 2008-11 period. Yet the nominal quantity has doubled. So the real quantity has roughly doubled. people are demanding bigger real cash balances. Again, interest rates are the price of credit, not money.
    Suppose we were on a simple gold standard, where gold coins were money. They you’d use simple micro price theory to model the relative price of gold, as any other commodity, and you’d assume gold demand had gone up if you had both more gold and a lower price level (like the 1930s). Regardless of what happened to interest rates.
    Nick, I actually do not base my views of AD on my preference for NGDP targeting. Indeed I used the same approach years ago when I still favored price level targeting. Even now, when I teach price level targeting I don’t draw the AD curve horizontally, rather I use the same hyperbola, and illustrate it by showing that when there is a supply shock, the Fed must move the AD curve in tandem to keep the price level constant (perhaps worsening the recession.)
    I’m astounded by what I am reading from Kevin, Adam and yourself, but I have to assume you guys are right, as you’re probably more in tune with conventional Keynesian theory. So I’ve misunderstood how others interpret the model. But here’s what really astounds me. Me and almost every other economist stands in front of the class, showing what happens when AD shifts right and you have a vertical (classical) AS curve. And I’m now being told that when economists draw that rightward shift in the AD curve, they don’t actually mean to suggest that there has been an increase in AD. That’s quite amazing to me. But I guess it’s true.
    I also teach my students that the terms “AS” and “AD” are quite misleading, as they aren’t really supply and demand curves. That part I got all along. What I never envisioned is that a rightward shift in the AD curve is not an increase in AD.
    I’ve always thought AD should be called “nominal expenditure” and the model would essentially divide up macro into nominal shocks and real shocks, with no assumptions made about what causes nominal shocks (velocity is free to fluctuate.) That seems much more logical to me. Instead we’ve ended up with Krugman’s upward sloping AD curves. In my model (which seems much more straightforward), Krugman’s scenario would have the positive supply shock (say lower wages) causing the AD curve to shift left by more than AS shifted right.
    I wonder if students understand any of this.
    You said;
    “I’m going to side with Adam here. We don’t have data on Md or Ms. We only have data on M. ?”
    Suppose both the price and quantity of oil increased at the same time. Don’t we know oil demand has risen? Suppose the price (i.e. value) and quantity of money has increased at the same time?
    I was taught that M/P is real money demand. Doesn’t Laidler have a book modeling it? How can we not know what M/P is?
    I’m beginning to think I should never come back to blogging–maybe I have everything wrong. Remember when Friedman sarcastically criticized Temin’s argument that maybe the quantity of money fell in 1929-33 because the demand for money fell? Friedman pointed out that a fall in the demand for money is inflationary. Was Friedman also wrong? I guess if I’m wrong I’m in good company. 🙂

  37. Unknown's avatar

    Scott: “I’m beginning to think I should never come back to blogging–maybe I have everything wrong.”
    OF COURSE YOU SHOULD GO BACK TO BLOGGING! YOU ARE ONE OF THE VERY BEST OUT THERE!
    Even if you might be wrong on a few things. Imaginative original thinkers are often wrong on (at least) a few things. That’s a price well worth paying. And blogging is an arena where mistakes are less costly than normal, because nobody takes anything on a blog as gospel, and because feedback comes much quicker.
    OK, I was wrong in thinking your rectangular hyperbola AD curve came from your policy proposal of NGDP targeting. So let me try again. What are you holding constant when you draw your AD curve? M? MB? Suppose Y is the only thing that affects the demand for money. Even then, if the income elasticity of the demand for money isn’t unit-elastic everywhere, you won’t get a rectangular hyperbola AD curve.
    AD is not, by the way, conceptually the same as (nominal) expenditure. For example, the Cuban economy almost always has AD greater than expenditure. There is excess demand for goods (and excess supply of money). Qd is the quantity we want to buy, which may be greater than what we actually succeed in buying (when there’s rationing or line-ups).
    “But here’s what really astounds me. Me and almost every other economist stands in front of the class, showing what happens when AD shifts right and you have a vertical (classical) AS curve. And I’m now being told that when economists draw that rightward shift in the AD curve, they don’t actually mean to suggest that there has been an increase in AD. That’s quite amazing to me. But I guess it’s true.”
    I draw it exactly the same way as you. But I would say “In this case, an increase in AD (shift in the curve) didn’t cause an increase in AD (aggregate quantity of real output demanded).” Just to clarify my verbal sloppiness.
    “Suppose both the price and quantity of oil increased at the same time. Don’t we know oil demand has risen? Suppose the price (i.e. value) and quantity of money has increased at the same time?”
    OK. We don’t have data on Md or Ms, but we do have data on M and P. By looking at P, we can infer whether it was Md or Ms that increased (or which one increased more). OK.
    “I was taught that M/P is real money demand. Doesn’t Laidler have a book modeling it? How can we not know what M/P is?”
    If we are always in equilibrium, then Md=M=Ms. Similarly, Md/P=M/P=Ms/P.
    What we observe is the (real or nominal) money stock, not money demand or money supply. But are we always in equilibrium?
    Laidler wrote a lot of papers in the 1980s arguing for a buffer-stock conception of money in which, with sticky prices, people could be off their money demand curves. We observe the hot potato process (and the musical chairs game) working itself out in real time. The stock of money people actually hold is not always equal to their desired stock.

  38. James Hudson, alias Philo's avatar
    James Hudson, alias Philo · · Reply

    You write that “in a world where sellers nearly always sell you what you demand to buy (they don’t tell you to wait or join the queue), demand for spending nearly always equals actual spending.” This remark has shaken my confidence in my grasp of basic economic concepts. For you make it sound as though demand for spending is just willingness to spend, which one might express by an offer to spend. If I offer you $10 for an hour of your labor, that is $10 of demand for spending, so I am contributing (at least) $10 to AD. If you accept, and give me the hour in exchange for the $10, that is actual spending (by me). If you tell me you’re too busy today, but you’ll do it next week, I am contributing $10 to AD today, but not $10 of spending–that happens only next week (if at all; I may reject your offer). If you hold out for $15 and I accept that (so that it turns out that in spite of my lowball offer I was all along willing to spend $15), my contribution to AD is and always was $15 (and my contribution to actual spending is $15). If you simply refuse my offer, so that no spending takes place, my contribution to AD is still $10 (or whatever higher figure I would have been willing to spend); to spending, nil.
    But is this really how economists use the term ‘demand’–for the mere willingness to buy something (at a certain price), even if there is no seller (at that price)? If so, there’s an awful lot of what we might call “shadow demand,” based on idle, unrealistic wishes.
    Continuing with the rest of your answer (for which, by the way, I thank you): you have the monetarist saying that when there is an “increased supply of money, . . . people may try to lend out some of the excess money, rather than spend it themselves.” (Therefore interest rates fall.) I think this will be true only if prices are sticky; otherwise the increased money supply wouldn’t be excess. Now, it would be strange to assume that people in general do not realize that the money supply has (more or less permanently, we are assuming) increased; why would they not be aware of this, especially in the modern age of financial news media? And it is hard to see why, if they did realize this, prices would be sticky. But perhaps price-stickiness is, after all, (barely) compatible with a widespread understanding that prices will soon be going up; so let’s suppose everyone understands this. But we seem to be assuming that interest rates are not sticky: they adjust readily to the increased desire of money-holders to lend. So would not interest rates tend to rise, due to anticipated inflation–the “Fisher effect,” counteracting the contrary effect mentioned by the imaginary monetarist?
    Finally, we come to your direct answer to my question. You have the (New) Keynesian say: “A fall in r makes holding bonds less attractive, so people buy more goods instead.” This doesn’t look plausible. People become reluctant to buy bonds, and try to sell some of those they already own; so the price of bonds falls; so interest rates rise; so the fall in interest rates didn’t last long, after all!
    But perhaps I have asked too much: perhaps the (New) Keynesian view just isn’t plausible.

  39. RSJ's avatar

    “Sounds as though in 2001 the BoC switched from using 11.45am repos to maintaining a positive (but adjustable) early morning Cash Setting Target?”
    There is still the option to do repos, but according to the author, in that 2 year transition period, reserves were literally zero But when it was officially adopted, the system reserve position was set at +50 million. The author contends that there are frictions, search costs, some banks may have limits to how much they will lend to other banks, etc — so having a small (e.g. 50 million) net positive reserve position makes it much more likely that LTVS will take care of all the settlement needs without resorting to SPRAs or SRAs.
    But the main point is that the non-financial sector sees deposits + currency, whereas the CB is managing reserves. In order to get from a change in reserves to a change in deposits + currency, you need some assumptions about how the system works. That assumption could be a reserve multiplier, for example. Getting the assumptions right is important in determining whether there is a hot potato effect or just an interest rate effect.
    In a commodity money model without banks, there is clearly a hot potato effect. Households, in aggregate, literally cannot cause the quantity of money to change.
    In a fiat model with banks, and with a central bank, if households have too much money, they buy a bond from the banks and the problem is solved. This comes at the price of a decline in rates — they have to offer an attractive bid to get the bank to buy the bond (to get rid of the excess deposit), just as the CB needs to offer an attractive bid to get the household to sell their bond to the CB (to create an excess deposit). But for some reason you are assuming that households can only buy goods, and not bonds, and this is because you have no banks in your model.
    In equilibrium, the two bids will be the same, therefore you cannot talk about households voluntarily selling bonds to the CB in order to get more deposits, and then madly hot potato-ing goods to get rid of the exact same deposits they just (voluntarily) bought.
    It makes no sense to talk about HPE in a modern economy because the money held by the non-financial sector is unchanged as a result of OMOs.
    And we have data on this — during the Fed’s first QE (buying mortgages), households sold mortgage bonds to the CB, and bought treasuries (from the Federal Government), leaving their currency + deposit holdings slightly lower than before the operation began.
    In other words, even though the Fed bought large quantities of bonds, it failed to increase the money holdings of the non-financial sector.
    In the second round of QE, as the Fed was buying bonds from households, households were buying bonds from Treasury, so the consolidated government was still a net bond supplier to households. Again household deposit + currency holdings were unchanged. All that happened was that banks had excess reserves.
    Alternately, when China was buying up large amounts of treasuries, households sold them the treasuries and turned around and bought an equivalent amount of (newly created) MBS from the financial sector.
    In all of these cases, households were in full control over the quantity of bonds + deposits that they held. They held the quantities that they demanded to hold at the given rate — the CBs influence over the non-financial sector’s money and bond holdings begins and ends with the interest rate.

  40. Kevin Donoghue's avatar
    Kevin Donoghue · · Reply

    Scott: “I’m fine with that explanation, but still don’t see where you need interest rates to play a role in the transmission mechanism. You could imagine an economy with just cash and goods, no interest rates. Goods prices are sticky, 30% adjust each period. OMOs are done with some good, like gold. I’m arguing that the monetarist HPE does the job in that economy, and that expectations of it occurring also do part of the (short run) job in an economy that does have interest rates, and all of the long run job.”
    My contention is that your monetarist HPE effect is part and parcel of the NK model. Either that or I’m just wrong as to what you mean by the HPE. By all means let’s think of an economy where gold coins are the only money. We can prevent nominal interest rates from playing any role whatever in the transmission mechanism by having the interest rate pegged by law. The central bank has a huge stock of gold and it will lend all you can carry at that fixed rate. (I assume the rate is pegged at a high enough rate to ensure that the vaults will never be entirely cleaned out and also that Ponzi schemes are such a grave sin that nobody will contemplate them.)
    Now suppose some passing helicopter dumps crate-loads of gold in the main square and the citizens stuff their pockets with coins. Obviously we expect inflation to result. So where does it show up in the NK model? We certainly see it in the price-setting equation, derived from the firm’s profit maximization. 30% of firms will reset their prices right after the coins have been gathered up. They know that: (1) when a new steady-state is established, their marginal costs will be higher; (2) both prices and costs will rise in each period between now and then; and (3) they have only a 30% chance of being able to revise their prices next period and in each period thereafter. So of course they will raise their prices. The HPE effect also shows up in the household’s consumption decision, since the higher anticipated inflation reduces the real interest rate.
    Now if the potato is not hot enough for you, just increase the proportion of firms re-setting their prices each period to 60% or whatever looks right. What more do you want?
    As to whether you should resume blogging, I think you should be guided by Keynes’s precept: there’s no harm in being wrong if one is found out quickly. I think you can trust the blogosphere for that.

  41. Unknown's avatar

    RSJ: “In a fiat model with banks, and with a central bank, if households have too much money, they buy a bond from the banks and the problem is solved.”
    I frequently read Adam P and Matt Rognlie (and many others) saying something very similar. This, in fact, is at the root of the monetary orthodoxy I wish to challenge.
    Compare the following two sentences:
    1. If there is a bling bank that is willing to buy or sell unlimited amounts of bling at a fixed price of bling, then there cannot be an excess demand or supply of bling. If households hold too much/little bling, they simply go to the bling market and sell/buy that excess supply/demand to/from the bank.
    2. If there is a central bank that is willing to buy or sell unlimited amounts of money at a fixed price of money, then there cannot be an excess demand or supply of money. If households hold too much/little money, they simply go to the money market and sell/buy that excess supply/demand to/from the bank.
    The first is very plausible. And if you think in Walrasian terms, where money is just one of the n goods, the second will sound equally plausible.
    But is money just like any of the other goods? Is it right to think about money in Walrasian terms? First, there isn’t a money market. Second, the rate of interest is not the price of money. Third, we all hold money as a buffer stock, precisely because we cannot access all markets instantly and perfectly synchronise our payments and receipts. Fourth, each of us is willing to accept more money than we wish to hold precisely because it is money, and because we know that we, as individuals, can always get rid of it. A willingness to accept money in exchange for other goods is not the same as a willingness to hold money.

  42. anon's avatar

    “I frequently read Adam P and Matt Rognlie (and many others) saying something very similar. This, in fact, is at the root of the monetary orthodoxy I wish to challenge.”
    Part of the problem is that currency itself is an asset just like bonds are, in addition to it being a medium of exchange and a unit of account. Hence, it seems natural to analyze its convenience yield as the spread between the return on a short-term bond and the return on money (zero in nominal terms). Which is the nominal interest rate.

  43. Adam P's avatar

    Nick and Scott: “Second, the rate of interest is not the price of money”
    The problem here is that if that’s true then neither is 1/P the price of money. Or, we could equally say both are the price of money.
    After all, if apples cost $1 each, bananas $2 each and oranges $3 each then the price of of an apple in oranges is 1/3, in banans it’s 1/2 and in dollars it’s 1.
    As Scott says, the supply of money has increased and its price in terms of goods has stayed the same. Thus, the relative demand for money vs the demand for goods has increased.
    HOWEVER….
    The supply of money has increased but it’s price in terms of bonds has fallen, so demand for money relative to bonds has fallen.
    So has the demand for money risen or fallen? One answer is “neither, it depends”. Another answer is that it has fallen but the demand for goods has fallen more. But it is nonesense to claim that it has unambigously risen.
    Where talking general equilibrium here, you need all three markets ala http://web.mit.edu/krugman/www/islm.html

  44. Unknown's avatar

    Adam: fair point. It would be even better if the bonds were some sort of real bonds, so the price of those real bonds would permanently rise in the long run (when P is flexible) if the supply of money increased.
    “Where talking general equilibrium here, you need all three markets ala http://web.mit.edu/krugman/www/islm.html
    No! That should be TWO markets! Three goods (money, bonds, output) – two markets (bonds, output) in a monetary exchange economy 😉
    anon: yes. If all we have is a Walrasian hammer, it’s awfully tempting to treat money as just one more asset nail.
    Put it another way. In the sort of world where people could instantly resolve an excess demand or supply of money by swapping money and bonds, we wouldn’t hold or use money.

  45. Adam P's avatar

    Ok, two markets, 3 goods.
    So, if it’s a fair point then do you agree that the problem was not/is not an excess demand for money?

  46. Unknown's avatar

    Adam: nope. Because, “In the sort of world where people could instantly resolve an excess demand or supply of money by swapping money and bonds, we wouldn’t hold or use money.”. I expect I ought to do another post on this. Oh God. I can’t do yet another weirdo monetary theory post!

  47. Adam P's avatar

    I knew you’d say that:)
    But again, since the evidence points to the supply of money increasing but not the demand where’s your evidence.
    I don’t understand what relevance your quote has to this discussion. There was never any excess demand for money to resolve!

  48. RSJ's avatar

    Nick,
    You lost me @9:18. But then what is your explanation of why, after the CB bought a trillion dollars of bonds, household currency + deposit holdings were unchanged? Try to noodle out how something like that can happen, and see how it fits into your “bling” framework. I honestly don’t understand your bling framework, or what relevance it has to household deposit holdings.

  49. Joe's avatar

    Professor Sumner,
    You said…. “I don’t follow your other point about supply and demand not changing. Expectations of the future are one of the most powerful determinants of current supply and demand, especially in asset markets. So if the expected future price rises, the current demand rises and the current supply falls, leaving prices higher and quantities unchanged in the very short run.”
    My confusion is because this response is a direct contradiction from the following quotes….
    Don’t forget that in a ratex world the anticipation of the HPE makes prices rise even before people spend the money.
    But you said just a second ago in your response that the change in expectations created the current HPE/AD that causes the increase in asset prices. Here you say the exact opposite.
    As the cash falls out of the airplane onto Bora Bora, the natives tell the person about to buy a mango that they changed their mind, the price will now be x% higher, where x% is the expected increase in the money supply from the airplane drop.
    Once again, the contradiction to the response. The natives are increasing the price of mangos without first experiencing an increase in demand. How can that be? You have created two separate stories of how changes in expectations affect prices.
    There are countries where retailers put signs in windows that everything is x% above the sticker price, after a sudden currency depreciation.
    Once again, this is a contradiction from your response. In the first, changes in expectations cause changes in supply and demand and THEN asset prices change. Here, you are saying that asset prices changes before those markets experience a changes in supply and demand.
    Do you not notice the particular funny little difference in the stories. Your first story is: Change in expectations -> change in supply/demand in asset market-> change in asset prices. The second story is: Change in expectations -> change in asset prices.
    No?

  50. Scott Sumner's avatar
    Scott Sumner · · Reply

    Nick, Don’t laugh, I hold nominal expenditure (MV) constant when I draw the hyperbolic AD curve. That’s a tautology. But I don’t assume NGDP targeting, rather I treat any shift in NGDP as a change in monetary policy, even if it’s a failure to offset a move in V. Here’s how I approach the model. You have nominal expenditure determined by the interaction of M-policy and velocity shifts (fiscal policy, etc). That moves NGDP around. Then sticky wages give you an upward sloping SRAS. As NGDP rises, firms are willing to supply more real output, due to sticky wages. Where you tend to see sticky prices leading to more aggregate(quantity) demanded (AD), I see sticky wages leading to more real (quantity) supplied. AD shifts, quantity supplied responds. You call it an increase in AD, meaning real quantity demanded, for obvious reasons I don’t call it an increase in AS, that would confuse the AD curve and resulting quantity supplied.
    Yes, short run monetary disequilibrium is possible, but I would still give the same answer to Adam. For me, money is the base. My cash holdings are rarely in disequilibrium for more than the time it takes to get to a ATM. So if the base doubles in real terms for three years (2008-11), I’m comfortable calling that the new equilibrium. People and banks want to hold much larger real cash balances. I do think it is standard practice to assume the central bank determines M, and the public determines M/P (i.e. real money demand). And then try to model why M/P changes in response to interest rates, income and other factors. That’s what Laidler did. So I think my definitions are pretty standard in that area, (but not in AD I guess.)
    Kevin, You might be right about the NK model, I was relying on an answer Nick gave me earlier–he said they usually just model inflation, not the price level. The HPE allows you to model the price level, at least in a very rough way. Take New Zealand, where NGDP is about 50 times currency holdings. Suppose New Zealanders like to hold enough cash on average to buy a week’s worth of NGDP. That gives you the velocity of 52. Now triple the money supply. The HPE says they’d still want to hold about enough cash to buy a week’s worth of NGDP. At least in the long run. So the long run price level and NGDP triples. The NK model also predicts inflation will occur. The extra cash will lower interest rates, drive up AD, and eventually drive up prices. What I’m trying to understand is whether the NK model explains how high prices rise in the long run. Does it just predict much higher prices, or does it use the HPE to generate a prediction that the new equilibrium price level will be three times higher? The Post Keynesian model doesn’t tell you that. It doesn’t pin down the price level. I thought the NK did (via the HPE), until Nick contradicted me. Or else maybe I misunderstood him or he was just referring to a simplified NK model, not the fully fleshed-out model. So I am willing to be corrected. Krugman does sometimes use a QTM approach, so I assumed it was in the NK model.
    I wrote the preceding before reading your helicopter example, but my question remain. That example predicts higher prices, but I say the HPE gives you a specific (QT of M) prediction for how much higher. The fact that people and businesses will spend more, doesn’t tell us anything about how much higher prices will end up.
    I’m not impressed by models that explain the rate of inflation, I want to know why the current price level is not 100 times higher, or 100 times lower than right now. I believe only QT models can do that. Certainly the General Theory cannot. I also believe that if one can’t explain the level of prices, any model of inflation will be highly flawed. It will seem to work at low rates, but spin out of control in 1970s-style inflation.
    I plan to start blogging after the 4th of July, and I’m counting on you to come over and tell me when I’m wrong–you were one of my best critics.
    Adam P. In microeconomics the only price of apples that matters is the real price, the price relative to all other goods. That’s the price on the vertical axis on a S&D diagram. Because the nominal price of a dollar bill is always 1, the real or relative price of a dollar is 1/P. So I am being completely consistent. I also had a few comments on money demand in my reply to Nick.
    Everyone, Thinking about this discussion, and reading Krugman’s new Keynes essay, makes me wonder whether there is any other field where even well-informed people think about basic concepts in such different ways.

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