ISLM: what is it good for?

The ISLM model persists in most undergraduate textbooks, and even though it has vanished from graduate courses*, it remains central to the way economists think about policy issues.  The main reason it survives is not so much that it allows a relatively simple intro to policy issues to undergrads, as some argue, but the fact that it captures the interaction between real and monetary phenomena which was central for Keynes’ General Theory (still worth reading), and is flexible enough to accommodate divergent views, often reflected in different inclinations of the curves.

It is also true that the conventional interpretation of the ISLM is fraught with problems.  But the ISLM model is incredibly flexible and can accommodate most critiques.  For example, a few years back a reader asked Mankiw why he still taught that the Fed controls money supply, rather than control the rate of interest, which would be more relevant.  His reply was not particularly good (just an ad for his book), but the fact remains that it is easy to change the LM to reflect the fact that central banks control the rate of interest.  The ISLM with a horizontal LM is sometimes referred to as the ISMP, where MP stands for monetary policy rule, and for the most part this is done for the benefit of students (i.e. you can buy the new text with the updated ISMP model for $150!).

The ISLM can also accommodate an investment function in which the level of activity, rather than the rate of interest, is central, which is more empirically accurate, and different consumption functions in which other elements besides disposable income appear.  More importantly the ISLM does not imply a natural rate of unemployment, which often appears in the supply side part of the macro course.  In other words, the ISLM allows for relevant discussion of policy issues, and clarification of policy differences.  Besides, compare this model with the consumption theory you get in micro, and this is still one of the most relevant things you can learn in economics.  The other would be not to trust economists!

* David Colander suggests that it’s not taught in graduate courses because more sophisticated dynamic stochastic general equilibrium models (DSGE) are more important.  DSGE models are based on the aggregation of individual maximizing behavior, and have been less relevant for policy analysis than old fashion macroeconometric models based on the old Keynesian theory.  The whole conference on the ISLM, in which you can find Colander’s paper is available here

.

Teaching macroeconomics: the resilience of the ISLM model

Teaching ISLM this and next week. I have posted in the past on this, so I'll just put the links below to the relevant posts.

ISLM: What is it good for?

ISLM: a further explanation and a defense

Krugman is actually right on ISLM and Minsky

There are more posts that deal with some relevant issues that you can access if you click on the ISLM label below.

The interesting thing is that, although the ISLM is less used in theory, in particular because the multiplier story at the core of the IS has been substituted by a Ramsey intertemporal maximization story and the LM has been substituted by a Wicksellian interest rate rule, it is still the workhorse of macroeconomic teaching, and likely of simple policy thinking. In many ways the ISLM remains a much better basis for thinking about the economy than modern New Keynesian DSGE models (if nothing else because of the multiplier).

ISLM: a further explanation and a defense

I noted before  the traditional representation of the ISLM is problematic. Yet as I also noted the ISLM model can accommodate changes that incorporate the criticisms of classical-Keynesian, post-Keynesian and other heterodox groups. There is no need for an investment function based on the marginal productivity of capital and the principle of substitution. The accelerator can be incorporated, and the inverse relation with the rate of interest would result from the effects of interest rates on other components of demand. Also, endogenous money can be incorporated easily, and for the most part this has been done in New Keynesian models (the ISMP).

In the post (linked by David here) that prompted this sort of defense of a changed ISLM, Lars Syll correctly notes that New Keynesians are often right on policy, but incorrect on theory. And I for the most part agree with Lars intentions. Yet, he suggests that the problem lies in that:

"If macroeconomic models – no matter of what ilk – assume representative actors, rational expectations, market clearing and equilibrium, and we know that real people and markets cannot be expected to obey these assumptions, the warrants for supposing that conclusions or hypothesis of causally relevant mechanisms or regularities can be bridged, are obviously non-justifiable."

As I noted in my debate with Noah Smith, the problem with marginalism (neoclassical economics) is NOT rationality, utility maximization or supply and demand (not quite the same list raised by Lars). Here I would add that although one can certainly add heterogenous agents, assumptions that simplify and assume representative agents maximizing profits, for example, are not really problematic at all. Classical political economists and Marx did assume something like that and still did not reach the conclusion that the system was efficient in the sense of providing full utilization of resources.

Also, the idea that agents use all information per se is not necessarily bad (Tom Palley favors some sort of rational expectations, which he refers to as model consistent; see his old manual here). The problem is that the model used, by New Classical and other mainstream authors, has logical problems. Last but not least equilibrium per se is not a bad concept (on this there is the whole thing that Post Keynesians have inherited from Joan Robinson that makes things confusing for many heterodox economists). Equilibrium is actually quite essential for long-term analysis. And I would actually argue that it is relevant since it DOES have real world applications. In other words, real economies do fluctuate around long-term equilibrium positions that are sub-optimal.

The problem with mainstream theory is the notion of a natural rate, which is based on the principle of substitution which allows for 'factors of production' to be fully utilized. These are the problems that Keynes, by negating the idea of a natural rate, and Sraffa, by showing the logical problems of the principle of substitution, undermined. An ISLM without the natural rate is not only possible, but actually reasonably good as a tool for analyzing real economies.

PS: Note that Keynes wrote to Hicks on the ISLM that: "I found it very interesting and really have next to nothing to say by way of criticism." Keynes did not criticize the investment function in Hicks model, but note that this problem also was integral to the General Theory (GT). And yes Keynes was being nice, but he was nice too about Harrod's review of the GT, but did tell him that he did not mention effective demand.

Oskar Lange theory of interest and the ISLM

By Roberto Lampa (Guest blogger)

In two previous posts, dated 2011 and 2013, Matías Vernengo clarified that the ISLM model can accommodate changes that incorporate the criticisms of several heterodox groups. In particular, he stresses that the ISLM can accommodate an investment function in which the level of activity (rather than the rate of interest) is central, so that the accelerator can be incorporated. More importantly, he also states the ISLM does not imply a natural rate of unemployment, thus allowing for relevant discussion of policy issues.

Both these aspects can be found in Oskar Lange's 1938 contribution to the neoclassical synthesis, in which he assumes that investment (mostly) depends on consumption, which in turn is permanently distorted by the “irrational” distribution of income, typical of any capitalist economy. More precisely, Lange outlines the mutual dependence of investment and consumption as a sort of ‘indirect’ relationship.

Firstly, he states that, as in traditional theory, in his model an increase in the propensity to save induces a decrease in the rate of interest. However, his reasoning runs along more unconventional lines than the (Neo)-Classical interaction of both supply (of) and demand (for) capital curves:

"…an increase in the propensity to save [implies that] expenditure on consumption is now lower. This causes (…) a lower quantity of investment (…). Total income decreases (…). The consequence is a fall in the rate of interest." (pp. 17-18)

In other words, in Lange's view the immediate effects of an increase in the propensity to save are a decrease in consumption, investment and total income. Therefore, as recognized by Keynes himself:

"The analysis which I gave in my General Theory of Employment is the same as the ‘general theory’ explained by Dr. Lange on p.18 of his article, except that my analysis is not based (as I think his is in this passage) on the assumption that the quantity of money is constant." (Keynes J.M., 1973a, p.232n)

Following this train of thinking, we deduce that it’s only afterwards that the decreased level of the rate of interest will stimulate investment, consumption and total income. The final result of an increase in the propensity to save will then depend on the ‘specific weight’ of each of these two effects.

Not coincidentally, Lange explicitly assumes in equation (3) – by drawing on Karl Marx's realization crisis – that consumption directly affects investment, as an excessive growth in saving (i.e. an excessive contraction of consumption, investment and total income) cannot be counter-balanced by the subsequent decrease in the rate of interest, as it destroys any incentive to invest, "at least in a capitalist economy where investment is done for profit" (Lange, 1938, p.23). He thus firmly rejects the (Neo)-Classical assumption that any abstinence from consumption implies automatically an increase in investment: according to him, such a direct relationship holds only until a certain limit (i.e. the optimum propensity to consume), beyond which the collapse of the demand for investment goods will drastically diminish investment itself. Therefore, the real issue becomes if and how it is possible to determine (and to maintain) such an optimum propensity to consume, given a market economy. Lange's opinion is definitely non-optimistic:

"In a society where the propensity to save is determined by the individuals, there are no forces at work that keep it automatically at its optimum, and it is well possible, as the under-consumption theorists maintain, that there is a tendency to exceed it." ( p.32)

In other words, the result of Lange's analysis converges with (and radicalizes, as well) Keynes' pivotal idea, that is, the tendency towards a chronic under-consumption crisis.

Recently, I have published a detailed analysis of this rather obscure work in the Cambridge Journal of Economics. I explore in depth Lange's theory of interest and its tortuous relationship with both Keynes’ General Theory (1936) and Hicks' synthesis (1937), developing two graphical models that show the non-linearity of Lange's investment function as well as the consequences of his equilibrium solution. Through an unedited manuscript, I also reconstruct Lange's beliefs about the chronic sub-optimality of the capitalist economy and his scientific endorsement of the socialist economy.

Full paper is available here.

P.S. It is worth noting that Keynes himself was prompted to reflect that Lange's article "follows very closely and accurately my line of thought" (Keynes, 1973a) notwithstanding the analytical differences. Lange was, after all, standing on the same "side of the gulf," as he clearly rejected the notion that capitalism could be a "self-adjusting system" (Keynes, 1973b).

Krugman is actually right on ISLM and Minsky

I tend to disagree a lot with Krugman, at least on theoretical issues. His brand of Keynesianism supposes that the system doesn't work because of imperfections. For him, the current slow recovery is due to the fact that the natural rate of interest is basically negative and you cannot use monetary policy to stimulate the economy (see critique of this here). However, on his recent debate with Lars Syll (and here; Brad De Long also posted here), a post-Keynesian, with whom I probably share a more radical interpretation of Keynes and its relevance for economic theory, Krugman seems to get things right.

The main points in Lars initial post, based on Minsky's book John Maynard Keynes is that traditional representations of Keynes do not emphasize the cyclical component of Keynes' theory and that true or fundamental (non-probabilistic) uncertainty is often ignored. Lars adds a little bit more on his response to Krugman and De Long, but essentially is the same argument. Keynes didn't like the ISLM (which is from a historical point of view difficult to defend, after all the only stuff he wrote on this, to Hicks, was quite positive, even if it is of little relevance), that it is static (not paying attention to cyclical or dynamic phenomena), and perhaps more interestingly that the interaction of real and monetary variables in the model is simplistic.

Krugman points out that the General Theory (GT) is NOT about cyclical fluctuations per se. It is about the determination of the long run level of output and employment, around which the economy fluctuates, and he correctly notes that cycles only appear as an afterthought in chapter 22 of the GT. And that is precisely correct. The GT is revolutionary because it suggests that with price flexibility (not price rigidity as in the old Neoclassical Synthesis or the New Keynesian stories) the system gets stuck in a situation of unemployment equilibrium. Emphasis on equilibrium. Yes, unemployment at less than full employment and output below its potential level are both together in an equilibrium situation.

Patinkin suggested that Keynes meant unemployment disequilibrium, since within the neoclassical framework, unless there is a rigidity of some sort, and the system should go to its long run equilibrium position with full employment. Minsky (1975, p. 268), in the book cited above, says that Keynesian economics should be seen as the: "economics of permanent disequilibrium." That has no basis on the GT. Actually, the GT would be a less radical book if it only said that with instability the system might be always in a disequilibrium position. Keynes was very radical since he argued that the very notion of a natural rate should be abandoned (on this Paul and Brad have a lot to learn). Some Post Keynesians tend to dislike the idea of equilibrium (echoes of Joan Robinson's late critique of the idea), which ends up making them closer in many respects to the modern mainstream authors with their dislike for long term equilibrium positions.

So the GT is not about cycles (Keynes' Treatise on Money, a very conventional and Wicksellian book was about cyclical disequilibrium caused by differences between the natural and banking rates of interest, which, interestingly enough is closer to Krugman's way of thinking than the GT, or than to Lars, who is aware of the limitations of the natural rate concept). But that's not all that Krugman got right this time.

He quotes the famous passage in which Keynes says that the system is not violently unstable (GT, p. 249). And while Post Keynesians are correct to note the relevance of fundamental uncertainty, it is important also to consider the stabilizing role of conventions and institutions, to which Keynes alludes. Expectations play a role, but investment is not completely volatile, and it was a problem for Keynes only when "the capital development of a country becomes the by product of the activities of a casino" (GT, p. 159). In fact, given the relevance of the accelerator in determining investment, the central role of expectations is about the level of demand. For example, in the US investment has been subdued since demand is not growing fast and there are not reasonable expectations that it will any time soon.

Where New Keynesians go wrong, and in this case is actually Brad, not Paul (but he would certainly agree) is on the relevance of the marginal efficiency of capital, criticized by Minsky (even though it's far from clear that Minsky abandoned it). Brad thinks that Minsky critique of it is myopic and basically a PR problem. He says that it is: 

"Short-sighted, in that it is not Hicks who would be Minsky’s long-run intellectual adversary but rather Freidman [sic], Lucas, and Hayek, and so building bridges to the Hicksians ought to be a very high priority."

Probably true, but from a policy point of view. From a theoretical point of view, Hicks use of the marginalist notion of an investment function inversely related to the rate of interest (something Keynes also used) implies that there would be a rate of interest low enough that would produce full employment, that is a natural rate, which would preclude Keynes' claim about unemployment equilibrium (and the absence of a natural rate). In other words, with the marginal productivity of capital you have that unemployment must be a disequilibrium situation caused by some imperfection that inhibits the system from reaching the natural rate.

And yes the capital debates are relevant since they show that the inverse relation is only possible in a one commodity world. No natural rate, and no need to think about imperfections. And that's why the comment by Lars on the connection between real and monetary variables being simplistic within the ISLM is right on the mark. The idea that the central bank controls a monetary rate, that may get out of whack with the natural, and that by manipulating it can affect real variables is limited at best.

PS: For my previous defense of a modified ISLM go here and here. 

ISLM, ISMP, DSGE and other models

From the Google Ngram Viewer.

Note that even though the ISLM is from 1937 (and yes it is in the GT, and Keynes did endorse Hicks formalization, as discussed here, and here), it is only in the 1970s that the term takes off. The ISMP, which substitutes a monetary policy rule for the LM, and includes as a result endogenous money into mainstream models (note again endogenous money is not central for heterodox models, since orthodox ones can incorporate it, as discussed here) takes over in the 2000s, as does the Dynamic Stochastic General Equilibrium models, in which the IS with a multiplier is substituted by a Ramsey model. So, given the trends, you should miss the good old ISLM indeed.

On the blogs

How To And How Not To Attack Marx's Economics -- Robert Vienneau thoughtful account of various topics on Marxist scholarship. There is also this post by Lord Keynes on the LTV, which he has been discussing more lately. My views are closer to Robert's point of view.

Germany's trade surplus is a problem -- New blogger Ben Bernanke continues with the savings glut theme, and in this case he is right. Germany surpluses hurt the rest of Europe. Germany should spend more and allow the rest of Europe to enjoy less austerity.

The Inbred Bernanke-Summers Debate On Secular Stagnation -- Steve Keen's take on the debate (mine here), which is not on the substance of the debate though (he will post more later). The problem for Steve is that they all are New Keynesians, I think. Not sure if that is a problem. Don't get me wrong pluralism is important, but not sure how an Austrian perspective, for  example, would help clarify matters.

Big data is watching you -- by Lambert Strether, via Yves Smith's Naked Capitalism. I was teaching on efficiency wages last week and told students about how much firms spend on monitoring. I remembered David Gordon's Fat and Mean, that had something to say about that.

Sir John and Maynard Would Have Rejected the IS-LM Framework for Conducting Macroeconomic Analysis -- Mario Seccareccia on the ISLM. Note that Hicks recantation is not particularly good. And regarding Mario's point about investment not being sensitive to the rate of interest (a point made here several times; it's the accelerator!) that does not mean that the IS is vertical. Other spending components might be affected by the rate of interest (e.g. consumption). I would say the problem with modern mainstream macro is that it abandoned (other than for teaching undergrads) the old ISLM. And also, everybody forgets that they not only abandoned the LM for the MP (which Mario notes, and that's just a flat LM), but that they abandoned the multiplier and the IS is based on an intertemporal Ramsey model (that's the problem; the return of Say's Law). On my views on the ISLM go here.

A Stagnating Minimum Wage has Left Low-Wage Workers Facing a Longer Climb to Reach The Middle Class -- EPI's snapshot by David Cooper. Title is self-explanatory. Topic discussed here recently.

PS: I noted that Bernanke, a Republican, is at the Brookings Institution and not at the American Enterprise Institute. I was under the impression, maybe incorrect, that Democrats went to the Brookings, a center-left think tank, and Republicans to the AEI, a center right one. Something has changed if a moderate Republican can make it into the AEI.

Krugman on Friedman, Austrians, and Paradise Lost

I was a bit busy this week and did not weigh in on Krugman's latest incursion (and here too) on the history of economic ideas. He correctly dismisses Conservative economists in pre-Keynesian times, and particularly Hayek (and Austrians), who suggested that recessions and depressions were useful, as not relevant. And also, notes Friedman was more sophisticated. He also notes correctly (as was pointed out here before), that Friedman used when he was forced to present a complete model and ISLM with a Phillips Curve, that was not very different from the more Keynesian versions of the model done by the Neoclassical Synthesis authors.

He is more positive about Friedman because:

"He [Friedman] was willing to give a little ground, and admit that government action was indeed necessary to prevent depressions. But the required government action, he insisted, was of a very narrow kind: all you needed was an appropriately active Federal Reserve... [But Krugman does not ] want to put Friedman on a pedestal... [since] the experience of the past 15 years, first in Japan and now across the Western world, shows that Keynes was right and Friedman was wrong about the ability of unaided monetary policy to fight depressions."

Note that Krugman also notes Friedman's critique of Austrian business cycle theory (see here), which shows that in spite of being marginalist and part of the mainstream, still the extreme laissez faire view makes them part of the fringes  of the profession. In other words, Austrians stand for the mainstream as the Tea Party stands for the more moderate right wing.

Perhaps the most important point in Krugman's reflection on the state of the profession is his confession that he used to consider himself "a free-market Keynesian — basically, a believer in Samuelson’s synthesis. But [he is] far less sure of that position than [he] used to be." Good enough. Note, however, that what he means by a 'free market' Keynesian is a peculiar mix.

The Neoclassical Synthesis, was based on Hicks ISLM and Modigliani's fixed wages. The fundamental idea is that with wage flexibility the system would lead to full employment, a proposition that Keynes denied in the General Theory. In addition, the capital debates have shown, and Samuelson admitted in 1966, two years before Friedman re-introduced the Wicksellian notion of a natural rate, that the neoclassical parable in which substitution led to full employment of factors of production does not hold.

So, beyond the ideological stance (which made more sense at the time of the Old Neoclassical Synthesis, during the Cold War) Free Market Keynesianism was always kind of a misnomer. Remember that Keynes in 1926 suggested that Liberalism (in the traditional European sense of Laissez Faire) was dead.

Who is the real revolutionary figure in modern macro, Friedman or Lucas?

 

Who's your daddy?

Just finished my summer macro class (last Friday actually; grades were due Monday). One of the things that always becomes important in the course is how to define the break between Keynes, or at least Keynes and the Old Neoclassical Synthesis, on the one hand, and Friedman and Lucas, in the case of the latter both the New Classical models (monetary misperception) and Real Business Cycle (RBC) models, on the other. Many authors suggest that Lucas should be considered, after Keynes himself, the great scientific revolutionary, and that Friedman's break is incomplete. It is the implicit view in Alessandro Vercelli's book  Methodological Foundations of Macroeconomics: Keynes After Lucas or explicitly in the more recent book by Michel De Vroey's Keynes, Lucas, d'une macroéconomie à l'autre.

The reasons adduced are associated to Friedman's model, which remains in many respects similar to the Neoclassical Synthesis one, that is, an ISLM with a Phillips Curve (PC) with gradual adjustment to the equilibrium position. In one sense it is true that in Lucas' equilibrium model endogenous variables are determined on the basis of real phenomenon, technology, preferences, and factor endowments. The model, which was further developed by RBC authors, emphasizes the intertemporal choices of between leisure and consumption, and the fact that production takes time, and requires inputs over several periods, and has led many to label it Walrasian, in contrast to the supposedly Marshallian model used by Friedman and the Neoclassical Synthesis Keynesians. The other significant difference is that stochastic processes, rather than deterministic ones, become relevant, and Dynamic Stochastic General Equilibrium (DSGE) became dominant [more on that in another post; issues have been dealt to some extent here].

Traditionally a Walrasian model is a General Equilibrium (GE) one, while a Marshallian model represents partial equilibrium. In that sense, the label is a bit of a misnomer, since the ISLM cum Phillips Curve model behind the Friedman’s aggregate demand and aggregate supply model is also a GE model. The Neoclassical Synthesis model solves for the simultaneous equilibrium of the goods, labor, money and bond markets. What Friedman added explicitly is the natural rate. The supply constraint.

The difference between Friedman and Lucas is really that in the Neoclassical Synthesis and Monetarist models some behavior is not derived from intertemporal maximization of individual agents, while that is not true in the RBC models. That should be seen not as a Walrasian feature, but as a result of the abandonment of the Principle of Effective Demand (PED), and the use of a Ramsey Intertemporal model to determine consumption. That is, a dynamic version of Say's Law. In that sense, like the New Classical School, the fundamental change, in this context, is that the equilibration between savings and investment is done by changes in the rate of interest, not income, and that only rigidities would deviate investment from full employment savings.

On the basis of these changes, it is hard to say that Lucas is the more revolutionary figure in modern macro. True, in Lucas framework, the main Monetarist conclusions are less effective or irrelevant. Only unanticipated monetary shocks have effects, and those are strange things to conceive. When shocks are anticipated, monetary shocks have no effects. However, when forced to discuss the Great Depression, Lucas admits that there is little evidence for the RBC view.

Lucas asks: “where is the productivity shock that cuts output in half in that period? Is it a flood or a hurricane? If it really happened, shouldn’t we be able to see it in the data?”* Lucas, even though he has accepted that most cycles are explained by productivity shocks remains convinced that the Great Depression resulted from a monetary contraction by the Fed, as in the Monetarist views of Friedman. And one wonders why that monetary contraction was unanticipated.

Also, even if more extreme, the results do not change the situation in the long run. That is, for Friedman too in the long run (anticipated or not) monetary shocks have no effects. The crucial theoretical variable is the natural rate.

In this sense, it seems that Friedman, and the return of the natural rate of unemployment, and implicitly the interest and output ones too, is crucial for explaining the return of the pre-Keynesian Wicksellian framework that is dominant with the New Macroeconomics Consensus (NMC). Even if Friedman had exogenous money, and a quantitative rule, rather than an interest one, and even if he believed in monetary shocks, rather than the real ones that Wicksell and modern macroeconomists emphasize. Modern macro is neo-Wicksellian, but it owes that to Friedman, more than to Lucas.

* Cited in DeVroey and Pensieroso here.

On Austrians and the natural rate of interest

I don't often write about Austrians. As I noted before the reason is that, as a school of thought, Austrians are kind of irrelevant. They are part of the marginalist mainstream, but are often confused as heterodox (sometimes even Austrians don't know that they are neoclassical). In fact, Hayek was for the most part forgotten after Sraffa and others showed the inconsistencies of his theories in the 1930s, and if Austrians understood the consequences of the capital debates, their come back in the 1970s would seem even less reasonable.

Throughout their underground period, from the 1940s to the 70s, they were part of 'secret' societies in which only the initiated (complete adherence to the ideology) could participate, like the Mont Pèlerin Society, and creating think tanks, like the conservative Institute for Economic Affairs (IEA), to promote the laissez faire ideology (note this had no basis in theory, since they cannot prove that markets produce efficient allocation of resources with a uniform rate of profit, but I'll get back to that below).

It was the rise of the conservative movement, a sort of Polanyian reaction to the Welfare State, that brought back all sorts of laissez faire cranks, and brought in the coattails Hayek and his disciples. In contrast to Milton Friedman, that used a fairly regular ISLM cum Phillips curve model, with the added natural rate, Hayek produced no relevant innovation, besides some poetry about the complexity of markets and uncertainty (which is why some confuse him with an heterodox author; blame Shackle for this).

Sissela Bok, the daughter of Gunnar Myrdal,* co-winner of the Sveriges Riksbank Prize with Hayek in 1974, recounts in her biography of her mother Alva [Alva Myrdal, Gunnar's wife received a real Nobel, the peace one in 1982] that the prize was given to Hayek by the Swedish economics establishment as a way to demean the prize. And if this is not enough, the guy that was supposedly for freedom, and for economic freedom because that one is central for political freedom, defended Pinochet. So really there is no economic or moral reason to take Austrians too seriously.

In sum, Austrians are really the most ideological wing of the neoclassical school, with all the other theoretical problems that the mainstream has. There is not much relevant to discuss there. So you might ask what is the post doing here. The reason is that there has a been a debate between Lord Keynes (nope not that one, the author of the very good blog Social Democracy for the 21st Century) and a Spanish Austrian author, and I was asked about my opinion. So here it is.

Some Austrians seem to think that their theory does not require a natural rate of interest. This might be the result of an incomplete understanding of Sraffa's 1932 critique of Hayek, in which he showed that there were as many own rates of interest (Sraffa's term) as commodities. At any rate, in the this recent debate the Austrian author says that in order to have a cycle Austrian don't need a natural rate and that:

"it suffices with showing that there is a mismatch between the term and risk structure that the marginal lenders (savers) are willing to fund and the term and risk structure associated with investment taking place in the economy." Or in Spanish in the original post: "le basta con mostrar que existe una descoordinación entre el plazo y el riesgo de las inversiones que están dispuestos a financiar los ahorradores marginales y el plazo y el riesgo asociados a las inversiones que se están efectuando en la economía."

So basically you need a mismacth between savings and investment. And dude, yes at the actual intersection of these two curves (often well behaved with savings being upward-sloping and investment downward-sloping) is an equilibrium interest rate, that would eliminate the mismatch. That's your natural rate. So, yes Austrians do have a natural rate**, even if they don't know it. Note that the capital debates show exactly that the idea of natural rate of interest inversely related with capital abundance (supply and demand) is not tenable. The poetry on market efficiency depends on being able to prove that. That's why the neoclassical project, and with it Austrians, has been derailed. It is really zombie economics.

* Myrdal coined the term monetary equilibrium to refer to the Wicksellian notion of an equilibrium between the natural and monetary or bank rates of interest. He also was a proto-Keynesian, and the key economist in the initial social democratic governments of the 1930s.

** According to Garegnani, in fact, even the inter-temporal Arrow-Debreu models, which supposedly do not have a uniform rate of profit, require a natural rate of interest to bring about the equilibrium of investment with full employment savings.

A primer on the economics of immigration: a surplus approach perspective

This is definitely not my topic of research. So you may very well ask why would I venture to write about it, beyond the obvious reason that it is probably one of the most debated issues these days in the US, with the government shutdown being related to the now infamous wall. I am myself twice an immigrant, I descend from immigrants (my parents returned to their country of origin, but had emigrated, and on my mother side my grandfather was also an immigrant, and the same goes on my father's side a few generations before), I might add. But that is not the whole, or the most relevant, reason.

Most debates about immigration center on labor market issues, and discuss the issue analytically with the tools of marginalism. The conclusions, by definition, are the logical consequence of the assumptions in that model, and the reading of the evidence is biased by those theoretical concepts. Here is a place were the capital debates (go read this very old post) might be important for a policy issue that is in the news constantly and that should concern economists. Being in favor of a return to the old and forgotten method of classical political economy, or the surplus approach, and not having seen any discussion of the issue along those lines is what led me to write this brief post.

Let me start with a very simple representation of the conventional argument. In the conventional story, you have a market for factors of production (labor in this case), and equilibrium is obtained when the marginal productivity of labor equals the marginal disutility of labor, where firms maximizing profits and individual workers maximizing utility find the optimal solution, shown in point C in the figure below (with variables with their traditional meanings; note I use N for labor, since I leave L, for liquidity; yep, I still teach the ISLM with that pesky L in there).

In this case, the effects of immigration are relatively simple to understand. Mainstream economics suggests that immigrants would add to the labor force, increase the labor supply, reduce the real wage, and lead to firms hiring more workers and increasing production. Output and employment should go up, while real wages would go down. The effect on the wage bill (W/p * N) depends on certain assumptions, but certainly native workers lose to the extent that their real wages go down. Hence, a backlash against immigration by working class native groups should be expected.

This simple analysis abstracts lots of things, of course. Differences in the quality (skills) of workers, and immigrants, and what would happen in the presence of capital mobility (with profits going up, with lower real wages, and capital mobility, then new factories should move into the country to take advantage of lower wages and increase the demand for labor, eliminating any initial effects on real wages). A lot of the academic debate has been based on arguments along these lines (see, for example, the Card and Borjas debate on the effects of the Marielitos Cuban immigrants in Miami real wages in this nice Vox post). Note, also, that the evidence suggests that the effects of immigration on real wages of unskilled workers are relatively small (if you believe Card).

In this view, then, there are some acceptable reasons for workers to be concerned with immigration. Note that this says nothing about fiscal issues, which many conservatives also use against immigration, suggesting incorrectly that they do not pay taxes (they certainly pay sales taxes, and other local taxes, and given the low incomes of most unskilled workers, would not qualify for income tax anyway), and take advantage of public goods. However, there are many analytical problems with the assumptions of the model above.

Note that the basis of the marginalist (or neoclassical) model presented above is the principle of substitution. In other words, as labor becomes cheaper than capital, that is by assumption fully utilized, then firms hire more labor. So the lower wages guarantee the full utilization of labor. The intensity of labor increases as its remuneration falls, and the price of labor, as any other price in marginalist theories (Austrian too, although they sometimes confuse this) reflects the relative scarcity of the factor of production. Note that for classical political economy authors (including Adam Smith) real wages resulted from historical and institutional factors, and supply and demand were only one of the factors affecting them. Under the conditions they analyzed the economies of their time they assumed that real wages were essentially at subsistence level.

The capital debates become relevant because they essentially show that the substitution principle has logical problems, and they open the possibility to a return of the sort of historical and institutional analysis of the labor market of classical political economics. I will not discuss the whole issue here again (check that post linked above), but the essence of the argument is that sometimes when real wages go down instead of leading to firms hiring more workers, the opposite might occur. Think of a situation in which real wages fall, and as a result, there is less demand for the goods produced by the firm. Perhaps the firms goods are bought by workers themselves.  Even though labor is cheaper, there is no reason for the firm to hire more workers if they cannot sell their goods, and the income effect overwhelms the substitution effect (the capital debates suggest that the substitution effect may go in the wrong direction, on top of that). That's essentially what Keynes said on chapter 19 of the General Theory (in chapter 2 he basically accepts the marginalist demand curve above, which is problematic, and shows the limitations of the supply curve; my paper on reading Keynes after Sraffa, the key author of the capital controversy, here).

The point is that it cannot be guaranteed that immigration would lead to a reduction of real wages, at least not on the basis of the logic of the model above. The actual result is ambiguous. Classical political economy provides an alternative framework to look at the labor market effects of immigration. It is clear that an increase of the labor supply might affect negatively the bargaining power of the established workers. But note that this is not always necessarily the case. Arguably, in the case of many immigrants in the so-called first globalization (late 19th to early 20th century), in which significant amounts of Socialists and Anarchists from Eastern and Southern Europe came to the US (and other parts of the Americas), the effect was to raise the class consciousness and the combativeness of the working class, helping strengthen some unions.

And the reverse is true, a country that experiences emigration might actually lose key workers, and unionization rates might decrease. In the last 30 years or so, the US has experienced an increase in the population of immigrants, many came from Mexico of course, and yet both countries have experienced a decrease in unionization rates (see here for Mexico). This suggests that other forces are in action, and that wage stagnation might be related to those policies, and not just, or not even fundamentally, as a result of the flows of workers from one country to the other.

Note also that classical political economy authors assumed that output was given in their discussion of distribution, and that separation of the theories of output and employment (dominated by Ricardian Say's Law, that was not a necessary feature of classical thinking, and that can be superseded by the Keynesian Principle of Effective Demand) allows us to understand other aspects of immigration. In other words, the level of output and employment would depend on autonomous spending (demand), and immigrants can easily be accommodated in society without displacing the native workers. Of course that would depend to a great extent on the government macroeconomic policies (not just fiscal and monetary policy, but also the setting of minimum wages, industrial and trade policy and so on).

In this view, it is less the effects of immigration on the labor market (along neoclassical lines of reducing real wages and increasing employment) that matter. It has been the policies that actually led to lower growth, lower union participation, trade policies that favored the loss of manufacturing jobs that have created the conditions for real wage stagnation. In that sense, it is those policies that are responsible for the backlash against immigrants among large groups of resident (native) workers, that could be exploited politically by right-wing populists, often with fascistic and authoritarian tendencies (not just in the US). Immigrants are actually escaping from similar neoliberal policies in their countries of origin.

And all of these points are just about the most direct economic consequences of immigration. There are other issues that are as relevant beyond economics. And it goes without saying that both immigrants and refugees (in particular those that result from US direct or indirect intervention abroad) deserve humane treatment, even if the conventional mainstream story was correct and immigration did cause inequality.