Saturday, December 31, 2011

Welcome

I study economics as a hobby. My interests lie in Post Keynesianism, (Old) Institutionalism, and related paradigms. These seem to me to be approaches for understanding actually existing economies.

The emphasis on this blog, however, is mainly critical of neoclassical and mainstream economics. I have been alternating numerical counter-examples with less mathematical posts. In any case, I have been documenting demonstrations of errors in mainstream economics. My chief inspiration here is the Cambridge-Italian economist Piero Sraffa.

In general, this blog is abstract, and I think I steer clear of commenting on practical politics of the day.

Monday, December 14, 2009

Wage-Rate Of Profits Curves

1.0 Introduction
I have written about so-called factor price curves and frontiers in many posts. They are so-called because the interest rate is not a price of any factor of production. In this post, I use the more neutral expressions "Wage-Rate of Profits Curve" and "Wage-Rate of Profits Frontier". I consider the concepts denoted by these terms to be elements of mathematical economics that arise, in particular, in the analysis of steady states.

2.0 Derivation of a Wage-Rate of Profits Curve
Consider an economy in which n commodities are produced. Each commodity j is produced in a corresponding industry in which it is the sole output of a single process. This process:
  • Requires inputs of labor and commodities. These inputs are represented as a0, j person-years per unit output and ai, j units of the ith commodity per unit output.
  • Exhibits Constant Returns to Scale (CRS).
  • Requires a year to complete.
  • Totally uses up its commodity inputs.
A technique consists of a process for each of the n industries. The technique is represented by the row vector a0 of direct labor coefficients and the square Leontief Input-Output matrix A. Assume:
  • Each commodity enters either directly or indirectly into the production of all commodities. That is, all commodities are basic in the sense of Sraffa.
  • The economy is viable. That is, there exists a level of operation of all processes such that the outputs can replace the commodities used up in their production and leave a surplus product to be paid out in the form of wages and profits.
  • Wages are paid at the end of the year.
  • The same rate of profits is earned on advances in all industries.
The assumptions of CRS and of all commodities being basic are made for ease of exposition.

Under these assumptions, the constant prices that allow the economy to smoothly reproduce satisfy the following system of n equations:
p A (1 + r) +w a0 = p
where p is the row vector of prices, w is the wage, and r is the rate of profits. Given the rate of profits, this is a linear system in n + 1 variables. The last equation imposed in the model sets the value of the numeraire to unity:
p e = 1
where e is a column vector denoting the units of each commodity that comprise the numeraire. Only solutions in which all prices are positive and the wage is non-negative are considered.

The price equation can be transformed into:
w a0 = p [I - (1 + r)A]
where I is the identity matrix. Or:
w a0 [I - (1 + r)A]-1 = p
where the assumption of viability guarantees the existence of the inverse for all rates of profits between zero and a maximum rate of profits. Right multiply both sides of the above equation by the numeraire:
w a0 [I - (1 + r)A]-1 e = p e = 1
The wage-rate of profits curve for the technique is then:
w = 1/{a0 [I - (1 + r)A]-1 e}

3.0 Properties of Wage-Rate of Profits Curves
The Wage-Rate of Profits Curve for a technique, under the assumptions above, has the following properties:
  • There is a finite maximum rate of profits for which the wage is zero. (If no commodity were basic, this maximum would not be finite.)
  • There is a maximum wage for which the rate of profits is zero.
  • The wage-rate of profits curve is strictly decreasing between the rate of profits of zero and the maximum rate of profits.
  • The wage rate of profits curve can be both convex to the origin and concave to the origin. (If the number of commodities n is greater than 2, the convexity can vary throughout the curve.)
  • If the vector of direct labor coeffients is a left-hand eigenvector of the Leontief Input-Output matrix, the wage-rate of profits curve is a straight line, that is, affine. (This is Marx's case of equal organic composition of capitals.)
  • If the numeraire is a right-hand eigenvector of the Leontief Input-Output matrix, the wage-rate of profits curve is affine. (This is the case of Sraffa's standard commodity.)
Figure 1 illustrates the wage-rate of profits curve for five techniques (α, β, δ, ε, and τ). Pasinetti uses π, not r, to denote the rate of profits. These curves are drawn under the assumption that the organic composition of capitals is not constant for any technique, and the numeraire is not the standard commodity for any of the techniques. Figure 1 also shows the wage-rate of profits frontier, formed from the outer envelope of all the wage-rate of profits curves for the individual techniques. This frontier is used to analyze the choice of technique for long-period, circulating capital models with single production.
Figure 1: The Frontier Formed From Factor-Price Curves (from Pasinetti (1977), p. 157)

Selected References
  • Heinz D. Kurz and Neri Salvadori (1995) Theory of Production: A Long-Period Analysis, Cambridge University Press
  • Heinz D. Kurz and Neri Salvadori "Production Theory: An Introduction"
  • Luigi L. Pasinetti (1977) Lectures on the Theory of Production, Columbia University Press

Paul A. Samuelson, 1915-2009

I've been influenced by Samuelson's work. I've referenced him here on such topics as:
  • Aggregate production functions
  • Cambridge Capital Controversies, Joan Robinson, and Piero Sraffa
  • Growth theory
  • International trade, theory of
  • Linear programming
  • Marginal productivity theory
  • Marxist economics
  • Revealed preference theory
I don't think I've referenced him on overlapping generations models when I've used them. But I believe he originated such models.

Wednesday, December 09, 2009

Negative Price Wicksell Effect, Positive Real Wicksell Effect

1.0 Introduction
I have previously suggested a taxonomy of Wicksell effects. This post presents an example with:
  • The cost-minimizing technique varying continuously along the so-called factor-price frontier
  • Negative price Wicksell effects
  • Positive real Wicksell effects
  • Price Wicksell effects greater in magnitude than real Wicksell effects.
This example is due to Saverio M. Fratini ("Reswitching and Decreasing Demand for Capital").

2.0 Technology
Suppose technology consists of a continuum of techniques indexed by the parameter θ, where θ is a real number restricted to the interval [0, 1]:
0 ≤ θ ≤ 1
Each technique consists of the three Constant-Returns-to-Scale processes in Table 1. No commodity is basic, in Sraffa's sense, in any technique in this technology. In the first process in a technique, θ-grade iron is produced directly from unassisted labor. In the second process, labor transforms the θ-grade iron into θ-grade steel. Finally, in the third process, labor transforms θ-grade steel into corn, the consumption good in the model. All processes take a year to complete, and all processes totally use up their input.
Table 1: The Technique Indexed by θ
InputsIndustry Sector
θ-Grade
Iron
θ-Grade
Steel
Corn
Labor (Person-Yrs)1/(1 + θ)θ3/(1 + θ)
Iron (Tons)010
Steel (Tons)001
Corn (Bushels)000
Output1 Ton1 Ton1 Bushel
Capital goods are specific in their uses in this example. θ1-grade steel cannot be made out of θ2-grade iron when θ1 ≠ θ2.

3.0 Stationary-State Quantity Flows
Suppose in Table 1 that:
  • The first process is used to produce (1 + θ)/(4 + θ + θ2) tons of θ-grade iron
  • The second process is used to produce (1 + θ)/(4 + θ + θ2) tons of θ-grade steel
  • The third process is used to produce (1 + θ)/(4 + θ + θ2) bushels corn
Then one person-year would be employed over these three processes. Capital goods would consist of (1 + θ)/(4 + θ + θ2) tons of θ-grade iron and (1 + θ)/(4 + θ + θ2) tons of θ-grade steel. The capital goods would be used up throughout the latter two sectors, but reproduced at the end of the year. Net output would consist of (1 + θ)/(4 + θ + θ2) bushels corn per person-year.

4.0 Prices
Given the technique, stationary state prices must satisfy the following three equations:
[1/(1 + θ)] w = p1
p1(1 + r) + θ w = p2
p2(1 + r) + [3/(1 + θ)] w = 1
where:
  • p1 is the price of a ton θ-grade iron;
  • p2 is the price of a ton θ-grade steel;
  • w is the wage;
  • r is the rate of profits.
A bushel corn is the numeraire. The above equations embody the assumption that labor is paid at the end of the year.

The above is a system of three equations in four unknowns, given the technique. It is a linear system, given the rate of profits. The solution in terms of the rate of profits is easily found. The so-called factor-price curve for a technique is:
w(r, θ) = (1 + θ)/[3 + θ(1 + θ)(1 + r) + (1 + r)2]
The price of a ton θ-grade iron is:
p1(r, θ) = 1/[3 + θ(1 + θ)(1 + r) + (1 + r)2]
The price of a ton θ-grade steel is:
p2(r, θ) = [(1 + r) + θ(1 + θ)]/[3 + θ(1 + θ)(1 + r) + (1 + r)2]
Given the technique and the rate of profits, these prices can be used to evaluate the value of the capital goods used in a stationary state.

5.0 The Cost-Minimizing Technique
The optimal technique to use at any given rate of profits maximizes the wage. The first-order condition for such maximization is found by equating the derivative of the factor-price curve to zero:
dw/dθ = 0
Or:
3 + θ(1 + θ)(1 + r) + (1 + r)2 - (1 + θ)(1 + 2θ)(1 + r) = 0
For 0 ≤ r ≤ 2, the cost-minimizing technique is then:
θ(r) = {[3 + (1 + r)2]/(1 + r)}1/2 - 1
For r > 2, a corner solution is found:
θ(r) = 1
Figure 1 illustrates the cost-minimizing technique.
Figure 1: The Choice of Technique
The graph in Figure 1 reaches a minimum at a rate of profits of (31/2 - 1). For (121/4 - 1) < θ < 1, two rate of profits have the corresponding cost-minimizing technique indexed by the given value of θ. In other words, this is an example of reswitching.

The index for the cost-minimizing technique can be plugged into the factor price curve for the technique to which it corresponds at a given rate of profits. Figure 2 displays the resulting so-called factor price frontier. The index θ varies continuously for 0 ≤ r ≤ 200% in Figure 2. As the rate of profits increases without bound, the frontier approaches a wage of zero.

Figure 2: The Factor-Price Frontier


6.0 Capital and Labor "Markets"
Fratini’s notes that this is a reswitching example in which the capital market initially appears to be in accord with out-dated neoclassical intuition. The above analysis has shown how to find physical quantities of capital goods per worker, how to evaluate them at equilibrium prices, and how to find net output per worker. Figure 3 shows the resulting plot of the value of capital per unit output. Fratini looks at the value of capital per worker instead. Either curve is continuous and downward-sloping. The regions above and below the rate of profits of (31/2 - 1) appear qualitatively similar and visually indistinguishable. This curve might be said to be a downward-sloping demand function for capital.
Figure 3: The Capital Market
The analogous curve looks very different for the labor market (Figure 4). The region with a positive Wicksell effect is a region with a high rate of profits and thus a low real wage. The demand function for labor might be said to be upward-sloping in the region with a positive real Wicksell effect.
Figure 4: The Labor Market

7.0 Conclusion
The example makes Fratini’s point. The shape of the relationship between the value of capital, either per worker or per unit output, and the rate of profits is not necessarily a good indicator of the presence of reswitching or reverse capital-deepening.

Saturday, December 05, 2009

Two Blogs Critical Of Economics

The post-autistic movement now has a blog: The Real-World Economics Review Blog.

I'm much less enthusiastic about the Counter-Economics Blog, which I stumbled over recently. Shaun Snapp claims to be applying critical thinking to economics, but he is too popular and too focused on finance for my taste. His claim that nobody reads either Adam Smith or Karl Marx is belied by the many serious scholars that do. (I've read major works by both.)

Wednesday, December 02, 2009

Herbert Gintis, Amazon Reviewer

Herb Gintis has now posted 231 reviews to Amazon. He has something to anger everybody.

Here he describes Jerry Cohen as a "supporter of virtually unsupportable Marxian doctrines" and having "studied ignorance of standard social and psychological theory."

He gives only two stars to Keen's Debunking Economics because, according to Gintis, it attacks a straw person. Mainstream economics is not as depicted by Keen, only undergraduate teaching is. "Abjectly brainless", "often just plain wrong", and "like teaching ... phlogiston and ether in physics class" are Gintis' phrases. I like how defenders of the mainstream cannot and will not defend economics as taught.

Gintis also gives only two stars to Ontology and Economics: Tony Lawson and His Critics. Basically, he disagrees that "Lawson's arguments are so powerful that few economists now feel that his case can be ignored." According to Gintis, his case can too be ignored; economists just ignore methodology. Gintis doesn't really engage the give and take in the book. I think he should have noted his agreement with John Davis's take on the openness of mainstream economics to some kinds of heterodox contributions.

I found this review of a recent George Soros book of interest. Some blame the current financial meltdown on failures of either individual or collective rationality. Gintis says that even if everybody were as rational as some (Chicago?) economists posit, market fundamentalism would still be unfounded. He bases this claim on the failure of the Arrow-Debreu model of General Equilibrium to have any attractive dynamical properties. He recommends agent-based modeling to analyze capitalist economies.

Gintis has quite a few positive reviews of rightists. For example, he gives four stars to Hazlitt's Economics in One Lesson. (Despite most of the reviews I'm highlighting, he also has some extremely positive reviews for liberals and leftists.) I think his reviews of right wing books generate more comments, and Gintis replies. (The worst are full of passionate intensity.) One review of a book that I would think is not worth reading currently has 103 comments.

In addition to politics and economics, he has also reviewed books on language, biology, and logic. I want to recall the existence of Torkel Franzen's Godel's Theorem: An Incomplete Guide to Its Use and Abuse.

Sunday, November 29, 2009

A Taxonomy Of The Effects Of Wicksell Effects

Consider a typical circulating capital model in which commodities are produced from commodities and labor. The technique in use is described by a square Leontief input-output matrix and a vector of labor coefficients. In a long run equilibrium, in which prices are stationary, the technique is selected from a set of techniques to minimize production costs at a given interest rate. That set is known as the technology.

Suppose the composition and quantity is taken as given, along with the interest rate and the technology. The difference in the value of the capital goods at two different interest rates is the sum of the price Wicksell and real Wicksell effects. The price Wicksell effect is the sum of the differences in prices among the capital goods for a given technique. But the cost-minimizing technique might not be the same at two interest rate. The real Wicksell effect is difference in the value of the capital goods for two techniques, given the price system at a one interest rate.

I want to compare the relative magnitude of price and real Wicksell effects at a given interest rate. Thus, I want to consider derivatives at a given interest rate. Therefore, suppose the technology consists of a continuum of techniques that might be eligible along the so-called factor price frontier. Table 1 shows all combinations of price and real Wicksell effect. A Wicksell effect is negative when the equilibrium at the higher interest rate has a lower value of capital, from the effects of price and quantity changes, respectively.

Table 1: Possibilities
Technology PropertyLabor
Market
Response
Capital
Market
Response
Price
Wicksell
Effects
Real
Wicksell
Effects
Higher
Wage
Lower
Interest
Rate
ANegativeNegativeLess
Employment
Increased
Value of
Capital
BNegativePositiveMore
Employment
Indeterminate
CPositiveNegativeLess
Employment
Indeterminate
DPositivePositiveMore
Employment
Decreased
Value of
Capital
EZeroNegativeLess
Employment
Increased
Value of
Capital
F?ZeroPositiveMore
Employment
Decreased
Value of
Capital
GNegativeZeroUnchanged
Employment
Increased
Value of
Capital
HPositiveZeroUnchanged
Employment
Decreased
Value of
Capital
IZeroZeroUnchanged
Employment
Unchanged
Value of
Capital

Row A in Table 1 conforms to the outdated neoclassical intuition of equilibrium prices as indices of relative scarcity. But, as Edwin Burmeister has noted, nobody knows what special case assumptions need to be imposed on technology to ensure that Wicksell effects happen to fall in any given direction.

I have the response in the capital market shown as indeterminate for rows B and C. The claim is that, for the case of a technology representable by a continuum of techniques, the price Wicksell effect can, but need not, swamp the real Wicksell effect. It is essential for this swamping to occur at a single interest that the technology be continuous. Pierangelo Garegnani, Heinz D. Kurz & Neri Salvadori, and Saverio M. Fratini have examples that illustrate some possibilities with a continuum of techniques.

Row E is the case of Samuelson's Surrogate Production Function. Price Wicksell effects are zero when the factor price curve for a given technique is a straight line. The question mark after the label for Row F reflects my belief that this row catalogs an impossibility. If factor price curves are straight lines along their entire length, capital-reversing cannot arise.

Rows G, H, and I are cases in which the real Wicksell effect is zero. The real Wicksell effect is zero in the discrete case when the factor price curves are tangent at a switch point. I'm not sure how this extends to the continuous case, in which all points along the factor price frontier are non-switching points. If the Row I case is possible, the technique is not determined by the location of the corresponding factor price curve. I think this may be so for non-straight line factor price curves, but I'm unsure about this case.

These remarks suggest a research program. First, demonstrate that no possibilities exist that are not listed in Table 1. This would seem to be obvious. But I don't understand Andreu Mas-Colell's paper "Capital Theory Paradoxes: Anything Goes" (in Joan Robinson and Modern Economic Theory (ed. by G. Feiwel) (1989)). He shows some multi-valued relations where I would expect functions. Second, for those rows that are impossible in Table 1, demonstrate this impossibility. Third, for each possible row, construct a numeric example. For rows B and C, one should construct at least two examples, one for each direction of the capital market response. I suppose a third example, in which price and real Wicksell effects are exactly matched in magnitude would be amusing. Much of this research would be non-original; many components are in the literature.

Sunday, November 22, 2009

Nietzsche On The Individual As A Society

I have previously noted the problems for utility theory created by the application of Arrow's impossibility theorem to a single individual. And I had quoted a number of classic authors who wrote of themselves as being composed of more than one mind. Here's another:
"'Freedom of the will' - that is the expression for the complex state of delight of the person exercising volition, who commands and at the same time identifies himself with the executor of the order - who, as such, enjoys also the triumph over obstacles, but thinks within himself that it was really his will itself that overcame them. In this way the person exercising volition adds the feelings of delight of his successful executive instruments, the useful 'underwills' or undersouls - indeed our body is but a social structure composed of many souls - to his feelings of delight as commander. L'effet c'est moi. What happens here is what happens in every well-constructed and happy commonwealth; namely, the governing class identifies itself with the successes of the commonwealth. In all willing it is absolutely a question of commanding and obeying, on the basis, as already said, of a social structure composed of many 'souls'." -- Friedrich Nietzsche, Beyond Good and Evil: Prelude to a Philosophy of the Future (Kaufmann translation), paragraph 19
By the way, the idea of modeling an individual choice with a structure underlying the textbook treatment of preferences over the elements of a linear space of commodities is not necessarily non-mainstream. I cannot say I know much about the relevant literature. However, I stumbled over an example - a paper, "Multiple Temptations", from John E. Stovall, a graduate student at the University of Rochester.