Krugman on (or maybe off) Keen

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Paul Krug­man has just com­ment­ed (twice) on my most recent blog about my paper for INET. In one sense, I’m delight­ed. The Neo­clas­si­cal Estab­lish­ment (yes Paul, you’re part of the Estab­lish­ment) has ignored non-Neo­clas­si­cal researchers like me for decades, so it’s good to see engage­ment rather than wil­ful (or more prob­a­bly blind) igno­rance of alter­na­tive approach­es.

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Fig­ure 1: Krug­man’s first piece

There is a bizarre asym­me­try in eco­nom­ics: crit­ics of Neo­clas­si­cal eco­nom­ics like myself read Neo­clas­si­cal lit­er­a­ture avid­ly, no because we agree with it—far from it—but because we feel oblig­ed to under­stand why they hold to their coun­ter­fac­tu­al views on the econ­o­my.

Most Neo­clas­si­cal econ­o­mists, on the oth­er hand, don’t even both­er to con­sid­er crit­ics with­in their own ranks—let alone crit­ics from with­out. So to have a paper referred to is def­i­nite­ly a plus.

In anoth­er sense, I’m appalled, because Krug­man’s com­ments put on dis­play that very igno­rance of Neo­clas­si­cal literature—let alone of alter­na­tive eco­nom­ic thought.

For instance, Paul refers to many of the propo­si­tions in my blog (it’s clear that he had­n’t read the paper on which it is based) as “asser­tions about what is cru­cial, with­out much expla­na­tion of why these things are cru­cial.”

One of these “asser­tions” is the key role of the change in debt—rather than sav­ing out of cur­rent income—in financ­ing invest­ment.

Well Paul, in that paper you will find ref­er­ences to the exten­sive the­o­ret­i­cal and empir­i­cal lit­er­a­ture from which that asser­tion was derived. I could start with non-Neo­clas­si­cal authors like Schum­peter, but let’s lead with some­one from with­in The Citadel (as Alan Kir­man once called the Neo­clas­si­cal ortho­doxy: Alan Kir­man, 1989, p. 126): Eugene Fama. The “asser­tion” that the change in debt was the main source of fund­ing for invest­ment was con­firmed by Fama and French in a pair of empir­i­cal papers:

The source of financ­ing most cor­re­lat­ed with invest­ment is long term debt. The cor­re­la­tion between I and dLTD is 0.79… These cor­re­la­tions con­firm the impres­sion … that debt plays a key role in accom­mo­dat­ing year-by-year vari­a­tion in invest­ment.” (Eugene F. Fama and Ken­neth R. French, 1999, p. 1954)

Debt seems to be the resid­ual vari­able in financ­ing deci­sions. Invest­ment increas­es debt, and high­er earn­ings tend to reduce debt.” (in an unpub­lished draft of the same paper).

Or con­sid­er Alan Holmes’s cru­cial paper in 1969, in which he fought an unsuc­cess­ful cam­paign against the lat­er exper­i­ment in Mon­e­tarism (far from being a “strict Mon­e­tarist”, as Paul jibes at one point, I and my Post-Key­ne­sian col­leagues and fore­bears take mon­ey seri­ous­ly while simul­ta­ne­ous­ly being tren­chant crit­ics of Fried­man’s sim­plis­tic Monetarism—see for exam­ple Nicholas Kaldor, 1982). Holmes, then Senior Vice-Pres­i­dent of the New York Fed­er­al Reserve, not­ed that the key Mon­e­tarist pol­i­cy pre­scrip­tion of reg­u­lat­ing the econ­o­my by “a reg­u­lar injec­tion of reserves” was based on “a naïve assump­tion” about the nature of the mon­ey cre­ation process:

The idea of a reg­u­lar injec­tion of reserves—in some approach­es at least—also suf­fers from a naïve assump­tion that the bank­ing sys­tem only expands loans after the Sys­tem (or mar­ket fac­tors) have put reserves in the bank­ing sys­tem. In the real world, banks extend cred­it, cre­at­ing deposits in the process, and look for the reserves lat­er. (Alan R. Holmes, 1969, p. 73)

Holmes would turn in his grave at Krug­man’s naïve asser­tion, half a cen­tu­ry lat­er, that banks need deposits before they can lend:

If I decide to cut back on my spend­ing and stash the funds in a bank, which lends them out to some­one else, this does­n’t have to rep­re­sent a net increase in demand. (Paul Krug­man, 2012)

As Randy Wray observed, that is “the descrip­tion of a loan shark, not a bank”—or of a hypo­thet­i­cal world in which banks need deposits before they can lend. In the real world, as Holmes points out above, bank lend­ing cre­ates deposits. That’s why banks mat­ter in macro­eco­nom­ics, and it’s not “Bank­ing Mys­ti­cism” to point this out: it is “Bank­ing Arm­chair The­o­rism” to ignore them in macro­eco­nom­ics.

Neo­clas­si­cal econ­o­mists have ignored this point for decades, which is why you have to look to the non-Neo­clas­si­cal lit­er­a­ture to tru­ly under­stand mon­ey cre­ation and the cru­cial role of banks. Schum­peter put it clear­ly dur­ing the last Depres­sion: he described the view that Krug­man puts today, that invest­ment (which is what the most impor­tant class of bor­row­ers do) is financed by sav­ings, as “not obvi­ous­ly absurd”, but clear­ly sec­ondary to the main way that invest­ment was financed, by the “cre­ation of pur­chas­ing pow­er by banks … out of noth­ing”. This is not “Bank­ing Mys­ti­cism”: this is dou­ble-entry book­keep­ing:

Even though the con­ven­tion­al answer to our ques­tion is not obvi­ous­ly absurd, yet there is anoth­er method of obtain­ing mon­ey for this pur­pose, which … does not pre­sup­pose the exis­tence of accu­mu­lat­ed results of pre­vi­ous devel­op­ment, and hence may be con­sid­ered as the only one which is avail­able in strict log­ic. This method of obtain­ing mon­ey is the cre­ation of pur­chas­ing pow­er by banks… It is always a ques­tion, not of trans­form­ing pur­chas­ing pow­er which already exists in some­one’s pos­ses­sion, but of the cre­ation of new pur­chas­ing pow­er out of noth­ing. (Joseph Alois Schum­peter, 1934, p. 73)

Fig­ure 2: Krug­man’s sec­ond piece

Why does it mat­ter that “once you include banks, lend­ing increas­es the mon­ey sup­ply”? Sim­ply, because the endoge­nous increase in the stock of mon­ey caused by the bank­ing sec­tor cre­at­ing new mon­ey is a far larg­er deter­mi­nant of changes in aggre­gate demand than changes in the veloc­i­ty of an unchang­ing stock of mon­ey. And in reverse, the reduc­tion in demand caused by bor­row­ers repay­ing debt rather than spend­ing is the cause of the down­turn we are now in—and of the Great Depres­sion too.

Fig­ure 3 shows the ratios of pri­vate and pub­lic debt to GDP in Amer­i­ca from 1920 till now. Non-neo­clas­si­cal econ­o­mists like myself, Michael Hud­son, Ann Pet­ti­for, the late Wynne God­ley, Randy Wray and many oth­ers (see Dirk J Beze­mer, 2009, and Edward Full­brook, 2010 for fuller lists of those who warned of this cri­sis before it happened–including of course Nouriel Roubi­ni, Dean Bak­er, Robert Shiller, and Peter Schiff) were shout­ing that the post-1993 explo­sion in pri­vate debt was unsus­tain­able, and would nec­es­sar­i­ly lead to a cri­sis when its rate of growth slowed (let alone turned neg­a­tive), for years before the cri­sis began (my first aca­d­e­m­ic warn­ing of the dan­gers of ris­ing pri­vate debt is shown as SK1, and my first pub­lic warn­ing that a cri­sis was immi­nent is shown as SK2 on Fig­ure 3). We were ignored, in large part because only Neo­clas­si­cal econ­o­mists like Krug­man, Bernanke and Greenspan had the ear of the pub­lic and politi­cians.

Now the cri­sis is the defin­ing eco­nom­ic event of our times, and years after it began, the only peri­od to which the recent boom and bust in the pri­vate debt to GDP ratio can be com­pared is the Great Depres­sion.

Fig­ure 3: Aggre­gate Pri­vate and Pub­lic Debt

Yet Neo­clas­si­cal econ­o­mists like Krug­man con­tin­ue to assert that the aggre­gate lev­el of pri­vate debt, and changes in that lev­el, are macro­eco­nom­i­cal­ly irrel­e­vant, when even casu­al empiri­cism implies that changes in the aggre­gate lev­el of pri­vate debt are asso­ci­at­ed with Depres­sions.

So while I wel­come any Neo­clas­si­cal econ­o­mist at the forth­com­ing INET con­fer­ence tak­ing up Krug­man’s call (“I hope some­one in Berlin press­es Keen on all this”), in real­i­ty Paul, empir­i­cal­ly ori­ent­ed non-Neo­clas­si­cal econ­o­mists like myself are the ones chal­leng­ing the unsup­port­ed asser­tions of Neo­clas­si­cal economics—not the oth­er way round.

Beze­mer, Dirk J. 2009. ““No One Saw This Com­ing”: Under­stand­ing Finan­cial Cri­sis through Account­ing Mod­els,” Gronin­gen, The Nether­lands: Fac­ul­ty of Eco­nom­ics Uni­ver­si­ty of Gronin­gen,

Fama, Eugene F. and Ken­neth R. French. 1999. “The Cor­po­rate Cost of Cap­i­tal and the Return on Cor­po­rate Invest­ment.” Jour­nal of Finance, 54(6), 1939–67.

Full­brook, Edward. 2010. “Keen, Roubi­ni and Bak­er Win Revere Award for Eco­nom­ics,” E. Full­brook, Real World Eco­nom­ics Review Blog. New York: Real World Eco­nom­ics Review,

Holmes, Alan R. 1969. “Oper­a­tional Con­straints on the Sta­bi­liza­tion of Mon­ey Sup­ply Growth,” F. E. Mor­ris, Con­trol­ling Mon­e­tary Aggre­gates. Nan­tuck­et Island: The Fed­er­al Reserve Bank of Boston, 65–77.

Kaldor, Nicholas. 1982. The Scourge of Mon­e­tarism. Oxford: Oxford Uni­ver­si­ty Press.

Kir­man, Alan. 1989. “The Intrin­sic Lim­its of Mod­ern Eco­nom­ic The­o­ry: The Emper­or Has No Clothes.” Eco­nom­ic Jour­nal, 99(395), 126–39.

Krug­man, Paul. 2012. “Min­sky and Method­ol­o­gy (Wonk­ish),” The Con­science of a Lib­er­al. New York: New York Times,

Schum­peter, Joseph Alois. 1934. The The­o­ry of Eco­nom­ic Devel­op­ment : An Inquiry into Prof­its, Cap­i­tal, Cred­it, Inter­est and the Busi­ness Cycle. Cam­bridge, Mass­a­chu­setts: Har­vard Uni­ver­si­ty Press.


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About Steve Keen

I am Professor of Economics and Head of Economics, History and Politics at Kingston University London, and a long time critic of conventional economic thought. As well as attacking mainstream thought in Debunking Economics, I am also developing an alternative dynamic approach to economic modelling. The key issue I am tackling here is the prospect for a debt-deflation on the back of the enormous private debts accumulated globally, and our very low rate of inflation.