Econometrics and equilibrium models

In Rational Econometric Man, Edward Nell and Karim Errouaki present a welcome and timely case for the view that econometrics and econometric model-building may not be the magic tools to solve all empirical questions despite what many seem to have thought they were in the 1960s. Here I examine some possible problems with econometric models that have to do with their usually taking the form of equilibrium models. Some of these problems were recognized by Trygve Haavelmo decades ago. And as Aris Spanos has recently discussed, the problems are often the result of what we say in our textbooks. Some problems have to do with what we mean by econometric parameters and others with how we use probabilities.     

Lost in intervention. The Harrod–Balassa–Samuelson effect on the peseta/dollar real exchange rate (1870–1998)

We have decomposed the peseta/dollar real exchange rate (1870–1998) into its trend and cyclical components and used the former to proxy its time-varying equilibrium. Then, we have compared changes in the equilibrium with changes in the Spanish and the USA productivity differentials to identify years that do not fit with the Harrod–Balassa–Samuelson (HBS) hypothesis. The greatest maladjustment is found in the 1940s and 1950s, decades of strong exchange rate intervention in Spain. Conversely, the link between equilibrium and differentials adjusts to the hypothesis when using the non-intervened peseta/dollar exchange rate on the Tangier black market. These contrasting results back up the idea that exchange rate intervention, so common in developing countries, might explain their scanter evidence in favour of the HBS effect.     

Modeling and Measuring Economic Reality: Reply to the Reviews

To begin with, we'd like to express our appreciation to our three commentators for their thoughtful and helpful reviews. Like the founders of the subject, we believe, and our reviewers seem to agree, that structural econometrics has the potential to enable us to develop serious working models of how different economies actually operate, and also to tell us something about the changing patterns of their growth and transformation. But both we and our reviewers agree that there is a great deal wrong with the way econometrics is practiced today.     

Analysing job creation effects of scaling up infrastructure spending in South Africa

In a first for South Africa, this article draws on literature on infrastructure productivity to model dynamic economy-wide employment impacts of infrastructure investment funded with different fiscal tools. Using a dynamic computable general equilibrium model, the South African investment plan is modelled, given the infrastructure externality. Alternative fiscal scenarios to finance the policy are modelled in the article. In the long run, unemployment decreases for all types of workers under one of the scenarios. In the short run, only elementary occupation workers benefit from a decrease in unemployment; for the rest, unemployment rises.     

Bond Pricing with a Time‐Varying Price of Risk in an Estimated Medium‐Scale Bayesian DSGE Model

New Keynesian model in which households have Epstein–Zin preferences with time‐varying risk aversion and the central bank has a time‐varying inflation target can match the dynamics of nominal bond prices in the U.S. economy well. The model generates a large steady‐state term spread and its fitting errors for bond yields are comparable to those obtained from a nonstructural three‐factor model, and one‐third smaller than in models with a constant inflation target or risk aversion. Including data on interest rates has large effects on variance decompositions, making investment technology shocks much less important than found in other recent papers.     

Lumpy Investment and Corporate Tax Policy

In the presence of both convex and nonconvex capital adjustment costs in a dynamic general equilibrium model, corporate tax policy generates both intensive and extensive margin effects via the channel of marginal Q. Its impact is determined largely by the strength of the extensive margin effect, which, in turn, depends on the cross‐sectional distribution of firms. Depending on the initial distribution of firms, the economy displays asymmetric responses to tax changes. Moreover, an anticipated increase in the future investment tax credit reduces investment and adjustment rate initially.     

Separate when equal? Racial inequality and residential segregation

This paper sets out a new mechanism involving the emergence of middle-class black neighborhoods that can lead segregation in American cities to increase as racial inequality narrows. The formation of such neighborhoods requires a critical mass of highly educated blacks in the population, and leads to an increase in segregation when those communities are attractive for blacks who would otherwise reside in middle-class white neighborhoods. To assess the empirical importance of this “neighborhood formation” mechanism, we propose a two-part research design. First, inequality and segregation should be negatively related in cross section for older blacks if our mechanism operates strongly, as we find using both the 1990 and 2000 Censuses. Second, a negative relationship should also be apparent over time, particularly for older blacks. Here, we show that increased educational attainment of blacks relative to whites in a city between 1990 and 2000 leads to a significant rise in segregation, especially for older blacks, and to a marked increase in the number of middle-class black communities. These findings draw attention to a negative feedback loop between racial inequality and segregation that has implications for the dynamics of both phenomena.     

Policy Consequences of Multiple Equilibria and the Indeterminacy of Economic Outcomes in a Boundedly Rational World: Closing the System with Non-Economic Variables1

In the conventional economic wisdom, the notion of unique equilibria that are efficient and Pareto optimal dominates the modeling discourse. Hebert Simon proposed an alternative analytical framework where the notion of multiple and sustainable equilibria is critical. Multiple equilibrium is the crucial stylized fact of economic life that requires better understanding and modeling. Of particular significance, Simon touched on the importance of institutions and differential power relationships in affecting economic outcomes. But this modeling approach was not well developed by Simon. Following from his contributions, further develop the notion of multiple equilibria especially in the realm of production with an emphasis on x-efficiency theory. I bring to bear the importance of institutional parameters (including power relationships), culture, norms, ethics, and moral sentiments to the determination of economic outcomes. In the model developed here, boundedly rational decision-makers’ choices are contextualized and constrained by complex environmental factors. No one choice is either inevitable or economically efficient. A multiplicity of outcomes is possible and sustainable inclusive of those that are suboptimal. Much depends on individual preferences and institutional design. This has significant implication for institutional design and policy.     

The Tunisia Wheat Market in the Context of World Price Volatility: A Stochastic Partial Equilibrium Approach

Food security is a key objective of agricultural and food policy in Tunisia. The 2007–2008 food crisis highlighted the negative impacts of price volatility on international markets both in terms of food insecurity and budget exposure. Tunisian food subsidy expenditures ranged from $180 million to $710 million in 2006–2010, so volatile world prices meant volatile subsidy costs. Moreover, cereal production in Tunisia still has much instability due to climate conditions, which also influences imports and, consequently, subsidy expenditures. This study applies a structural model to conduct stochastic analyses of trade and policy impacts on food security and budget expenditures in the Tunisian wheat market. The methodology disaggregates durum wheat and soft wheat markets and generates projections of import prices of durum wheat and soft wheat, using projections of world prices provided by the Food and Agricultural Policy Research Institute at University of Missouri (FAPRI-MU). The key innovation is the generated stochastic analyses of subsidy costs based on stochastic world price projections and stochastic domestic wheat yields based on historic yield variances. The analysis highlights the sensitivity of subsidy costs to world prices, volumes imported and domestic production, so that alternative policy tools can be considered.     

Sufficiency of an outside bank and a default penalty to support the value of fiat money: Experimental evidence

We present a model in which an outside bank and a default penalty support the value of fiat money, and experimental evidence that the theoretical predictions about the behavior of such economies, based on the Fisher-condition, work reasonably well in a laboratory setting. The import of this finding for the theory of money is to show that the presence of a societal bank and default laws provide sufficient structure to support the use of fiat money and use of the bank rate to influence inflation or deflation, although other institutions could provide alternatives.