Structure and understanding: Some observations on current activities in the field of structural modeling

Structural modeling has been under study in recent years as a method for dealing with complex societal problems, and is growing in acceptance as a tool for understanding complex social phenomena. Structural models demonstrate the interactions of the separate elements of a system and their combined overall effect. Thus, the nature of the problem for which this method of analysis is appropriate is different from complex problems of the traditional disciplines which lend themselves to reductionist approaches. This is because complex policy problems of society cannot be “solved” with precise analysis. Kenneth Boulding suggests that there are two ways to cope with a complex policy problem, either to “slice” the problem into partial equilibrium sections or “squeeze” it by aggregating numerous variables into a single index or macho variable. Structural modeling is an approach which comes under the general strategy of squeezing the problem and is promising because of the ability to include a range of macro variables which provide insights about social change. The articles in this issue treat several interesting aspects of this approach. In this article we wish to recall for consideration a central purpose for developing such methods. We have taken a historical approach to indicate some of the roots of the concern for the effect of technological process on social change. Within this context, we discuss the nature of the contributions made by the articles in this issue and what promise the methods offer to addressing the historical concern.     

A forecasting model for the market of competitive products

The classic way of performing a market forecast for industrial products implies an econometric analysis of the historical data of consumption and their projections into the future. The present work illustrates a fresh approach to the problem; the demand for the product under study is evaluated in a mathematical model which takes into consideration the technological and commercial characteristics of this product and correlates it with competitive and substitutive products. Competitiveness is measured by assigning merit scores to the characteristics of the different products, and calculating the relevant “weights of importance” on the basis of the historical consumptions. Forecasts of consumption are made by estimating the future scores of the characteristics and extrapolating the weights of importance. An example of complete application of the model to the textile market in Italy is included.     

Section 401(k), 403(b) and 457(b) plans: who can do what?

This article examines the three main types of supplementary pension arrangements. It focuses on their origins and development, employer eligibility, deferral and contribution limits, funding arrangements and other technical requirements as they have been affected by recent developments.     

Existence of Sparsely Supported Correlated Equilibria

We show that every N-player K ₁ × ... × K _N game possesses a correlated equilibrium with at least zero entries. In particular, the largest N-player K × ... × K games with unique fully supported correlated equilibrium are two-player games. We thank an anonymous referee for most useful comments. The first author acknowledges financial support from Spanish Ministry of Science and Technology, grant SEJ2004-03619, and in form of a Ramón y Cajal fellowship. The second author acknowledges support by the PASCAL Network of Excellence under EC grant no.506778, as well as from Spanish Ministry of Science and Technology and FEDER, grant BMF2003-03324. Both authors also acknowledge financial support from BBVA grant “Aprender a jugar.”     

Money substitutes and monetary policy in the U.K., 1922–1974

In the U.K., following the publication of the Radcliffe Report, it was widely believed that monetary policy was impotent because any attempt to make use of monetary policy would be fully offset by perfect money substitutes which were not controlled by the monetary authorities. This paper tests whether such substitutes exist. The technique is to fit a money demand function to a long run of data allowing the interest elasticity to vary from observation to observation, and using a procedure which permits infinite values of the elasticity. It was found that, although the elasticity does vary, no observation was consistent with the Radcliffe view. This was true for both interest rates tried, and the function proved very stable when tested. We conclude that the Radcliffe Hypothesis can be decisively rejected.     

Returns to scale and externalities in the consumption and investment sectors

Using data on US manufacturing, I estimate internal returns to scale and external effects for the consumption and investment sectors. I construct panels of data at the industry level and use results of gross output production function estimation to derive implied estimates in a value added specification. For the investment sector, returns to scale appear to be slightly increasing, with evidence of a positive external effect. For consumption, the evidence indicates decreasing to constant returns to scale. I discuss the implications of these results for the empirical plausibility of indeterminacy in recent multi-sector models of the business cycle.     

Choosing Among Regulatory Options in the United States Telecommunications Industry

We examine the determinants of the choice between rate-of-return regulation and incentive regulation in the United States telecommunications industry. We find that a state is more likely to select incentive regulation in any year: (1) when it has employed incentive regulation in the past; (2) when the Republican party controls both the executive and the legislative branches of the state government, but the Democratic party has controlled these branches historically; and (3) as the firms earnings under rate-of-return regulation increase toward the industry average. We also find that appointed regulators are more likely than their elected counterparts to revert to rate-of-return regulation.     

Threshold models for trended time series

This paper presents the theoretical development of a new threshold autoregressive model based on trended time series. The theoretical arguments underlying the model are outlined and a nonlinear economic model is used to derive the specification of the empirical econometric model. Estimation and testing issues are considered and analysed. Additionally we apply the model to the empirical investigation of U.S. GDP.This paper is the result of work carried out for the author's Ph.D. thesis. I would like to thank Hashem Pesaran for his help, encouragement and insights during the preparation of this paper. I also thank Gary Koop and Sean Holly for helpful comments. Financial assistance from the Economic and Social Research Council is gratefully acknowledged.