A system dynamics approach for studying the resilience of irrigation systems

One of the most interesting outcomes from the recent collaboration between natural and social scientists is the concept of resilience, which imported from engineering to ecology. The problem with that concept is that it is hard if not impossible to get simple measures for resilience as far as social-ecological systems are complex ones. Using a system dynamics model, the author shows that, for assessing resilience of systems like irrigation systems, it probably helps to see the process of resilience loss as a systemic one, in which dynamics is given by positive self-reinforcing loops, like the one we have labeled in this paper--the death spiral. The author also presents a list of symptoms of collapse in irrigation systems, in order to assess the resilience of those systems, and suggest some future avenues of research on the subject.     

A formal psychological theory for evolutionary economics

The purpose of this paper is to seek to rise to the challenge posed by Harstad and Selten by providing a single unifying model of the psychological processes underlying the behaviour which drives the process of economic evolution. It seeks, in short, to make evolutionary economics yet more intellectually competitive. A self-contained account is given of a new model of the psychology of economic behaviour developed at the University of Queensland as part of the legacy of the Brisbane Club of evolutionary economists. Two results derived within this model are presented - the “Schumpeter” and “Made to Stick” theorems - and are used to elaborate the centrality of knowledge and its growth to the behaviour which drives evolutionary processes in the economy. A core contribution of this paper is to identify the way in which knowledge thus evolves. These are then used to elaborate explanations of evolutionary economic behaviour on both sides of the production-consumption dichotomy, in particular the manner in which the growth of knowledge may be facilitated by interpersonal interaction and particular conditions in the mind, or personality types. We discuss some relevant policy aspects of the model before concluding. The intention of this paper is to provide a basis for future research aiming to build a more coherent, more comprehensive and more simple view of the behaviour driving evolutionary dynamics.     

The causes of bank failures: deflationary spells

Unexpected reductions in inflation induce debtor insolvency and bank failures with lags of up to eight years. Outside money is non-neutral because the default of marginal banks and the rising costs of surviving banks reduce the supply of monetary services.     

The formal sector wage premium and firm size

We show theoretically that when larger firms pay higher wages and are more likely to be caught defaulting on labor taxes, then large-high wage firms will be in the formal and small-low wage firms will be in the informal sector. The formal sector wage premium is thus just a firm size wage differential. Using data from Ecuador we illustrate that firm size is indeed the key variable determining whether a formal sector premium exists.     

The seasonality of banking failures during the late National Banking Era

Abstract.  In this paper, we expand previous models with banks and money and explore the consequences of seasonals in the banking system. We find that, when bank failures occur, not all of them have associated large output losses and currency premiums exist. We show that the most important sources of seasonal fluctuations for the banking system are those related to the return on farming activities and the scrapping value of the initial investment. Finally, this model is consistent with the notion that the Treasury is more likely to accommodate the money market in periods where the liquidity needs are higher. JEL classification: E50, F41     

New directions in predicting bank failures: The case of small banks

This paper uses five financial accounting ratios with three alternative loan-portfolio diversification measures to classify failures among small commercial banks that occurred during 1984. Classifications for one, two and three years before failure are performed using linear probability, logit, probit, and discriminant analysis models. Validation is done through the U-Method. The results indicate that the logit and probit functional forms may offer an advantage over the more frequently used discriminant analysis. U-Method classification accuracy is approximately 86 percent for the logit and probit models.     

Interest rates and investment coordination failures

The theory of capital developed by Bohm-Bawerk and Wicksell emphasized the roundabout nature of the production process. The basic insight is that production necessarily involves time. One element of the production process is to determine the period of production, or the length of time from the start of production to its completion. Bohm-Bawerk and Wicksell emphasized the role of the interest rate in determining the period of production. In this paper, I develop an option games model of the decision to invest. Two firms have an opportunity to enter a market, but production takes time. Firms face a two-dimensional decision. Along one dimension, they determine the period of production and the prospective profit therefrom. Along another dimension, they determine whether or not they want to enter the market given the amount of time it will take to start generating revenue from production. Within this option games approach, the period of production can be understood as an endogenous time-to-build and I argue that this framework provides a tool for evaluating the claims of Bohm-Bawerk and Wicksell against the backdrop of competition and uncertainty. I evaluate the period of production decision and the option to enter decision when the real interest rate changes. I show that investment coordination failures are more likely to occur at lower levels of profitability when real interest rates are low. I conclude by discussing the implications of low interest rates for boom-bust investment cycles.     

Public sector motivation and development failures

This paper provides a theoretical analysis of the relationship between public sector motivation and development. In the model the public sector produces a public good and workers are heterogeneous in terms of public sector motivation (PSM). Wages in the private sector increase with the quality of the public good. In this context, public sector wage premia (PSWP) have two opposite effects: low PSWP helps screen workers with PSM into the public sector, while high PSWP helps motivate workers to be honest. Raising PSWP may not improve the quality of governance and multiple equilibria might arise. The model highlights that the relative importance of workers selection and provision of ”on the job” incentives in the public sector varies in systematic ways with wages in the private sector. We provide anecdotal and original empirical evidence consistent with the theoretical predictions and discuss some policy implications for public sector reforms in developing countries.     

MOSES: Model for studying the economy of Sweden

MOSES is an aggregate econometric model for Sweden, estimated on quarterly data, and intended for policy simulations and short-term forecasting. After a presentation of qualitative model properties, the econometric methodology is summarized. The model properties, within sample simulations, and forecast evaluations are presented. We also address methodology and practical issues relating to building and maintaining a macro model of this type. The detailed econometric equations are reported in Appendix A.“I think it should be generally agreed that a model that does not generate many properties of actual data cannot be claimed to have any ‘policy implications’…”Clive.W. J. Granger (1992, p. 4).     

Functions and failures: how to manage technological promises for societal challenges

Technological promises are becoming part of the way in which scientific and technological communities try to attract the attention of stakeholders, aiming at legitimation, reputation, and funding. Not all promises, however, become reality. With the increase in the use of promises comes the risk of disillusion and cynicism, which may affect negatively policy-makers and the public opinion. The paper suggests that the introduction in the field of S&T and innovation policy of a tool commonly used in engineering fields aimed at identifying and measuring all possible failures of a proposed technology. Instead of focusing on the magnitude of promises, it suggests that a useful perspective can be gained by placing systematic attention to the negative side, i.e. all reasons why a given technology may fail to deliver the promises. The paper develops the methodology, presents a case study, and illustrates the benefits of using it in policy-making.     

The crowding-out effect of formal insurance on informal risk sharing: An experimental study

This paper investigates the crowding-out effect of formal insurance on informal risk-sharing arrangements via theory and laboratory experiment. Our model and simulation predict that the crowding out of private transfers is often more than one-for-one and will reduce the total risk coverage. Furthermore, the existence of a moderate degree of altruism exaggerates the crowding-out effect, especially when there is an ex-ante income inequality. These predictions are mostly supported by the laboratory experiment, except that the crowding-out effect is not more than one-for-one, and hence the total risk coverage is not significantly reduced by formal insurance.     

Determinants of bank failures in the US revisited

This study investigates factors influencing the bank failure rate in the United States over the period 1970 to 2007. The bank failure rate was found to be an increasing function of the unemployment rate, the average cost of funds, volatility of the S&P 500 Stock Index, and charge-offs as a percentage of outstanding loans and a decreasing function of the mortgage rate on new 30-year fixed-rate mortgages. The evidence implies also that the Federal Deposit Insurance Corporation Improvement Act acted to reduce bank failures whereas the Riegle–Neal Interstate Banking Act of 1994 may inadvertently have (by increasing competition and/or increasing costs through branch bank expansion) induced increased bank failures.     

Congestion games with load-dependent failures: Identical resources

We define a new class of games, congestion games with load-dependent failures (CGLFs). In a CGLF each player can choose a subset of a set of available resources in order to try and perform his task. We assume that the resources are identical but that players' benefits from successful completion of their tasks may differ. Each resource is associated with a cost of use and a failure probability which are load-dependent. Although CGLFs in general do not have a pure strategy Nash equilibrium, we prove the existence of a pure strategy Nash equilibrium in every CGLF with nondecreasing cost functions. Moreover, we present a polynomial time algorithm for computing such an equilibrium.     

Government policy and the probability of coordination failures

This paper introduces an approach to the study of optimal government policy in economies characterized by a coordination problem and multiple equilibria. Such models are often criticized as not being useful for policy analysis because they fail to assign a unique prediction to each possible policy choice. We employ a selection mechanism that assigns, ex ante, a probability to each equilibrium indicating how likely it is to obtain. We show how such a mechanism can be derived as the natural result of an adaptive learning process. This approach leads to a well-defined optimal policy problem, and has important implications for the conduct of government policy. We illustrate these implications using a simple model of technology adoption under network externalities.     

A formal model of theory choice in science

Summary. Since the work of Thomas Kuhn, the role of social factors in the scientific enterprise has been a major concern in the philosophy and history of science. In particular, conformity effects among scientists have been used to question whether science naturally progresses over time. Using neoclassical economic reasoning, this paper develops a formal model of scientific theory choice which incorporates social factors. Our results demonstrate that the influence of social factors on scientific progress is more complex than previously thought. The patterns of theory choice predicted by the model seem consistent with historical episodes of theory change. Received: April 8, 1997; revised version: April 30, 1998     

Tanzanian formal sector workers' participation in informal production

A theoretical model is developed explaining formal sector workers participation in the informal sector. A reduced-form informal sector participation function is derived from a specific utility function, a specific informal sector production function, and a specific informal sector earnings function. The participation function can be estimated consistently, and provides a solution to the problem that informal sector ‘wages’ in developing countries are hard to observe. A sample of Tanzanian formal sector workers is used to estimate the participation function. A majority of Tanzanian formal sector workers participate in informal production. Participation in informal production is inversely related to household income, to living in Dar es Salaam, and to being a mother with small children. Participation is positively related to age, and multiple-job-holding seems to play a very different role in the transition from work to retirement in Tanzania compared to industrialized countries.     

The growth of knowledge: Testing a theory of scientific revolutions with a formal model

Modern theories of science emphasize scientific revolutions rather than the traditional cumulative view of scientific progress. Thomas Kuhn, in particular, has formulated a theory of science based on the lifecycle of paradigms. Though Kuhn's theory is attractive, no calculus is offered by which the theory can be tested. This study tests the dynamic consistency of Kuhn's theory by formalizing the theory and testing it with a computer simulation model. The model plays the roles of the actors, tracing out the consequences of their day-to-day actions. Sensitivity tests are used to explore the importance of various hypotheses. Results show the theory to be dynamically consistent: The lifecycle of paradigms described by Kuhn can be accounted for by Kuhn's theory. Kuhn's theory thus passes a test to which few other theories of science have been subjected. The study shows how modeling can provide a method for testing theories even when those theories are stated entirely in qualitative terms, at a high level of abstraction, and in a context divorced from explicit dynamic analysis.     

Evolutionary stability of bargaining and price posting: implications for formal and informal activities

In this paper we study the co-existence of two well known trading protocols, bargaining and price-posting. To do so we consider a frictional environment where buyers and sellers play price-posting and bargaining games infinitely many times. Sellers switch from one market to the other at a rate that is proportional to their payoff differentials. Given the different informational requirements associated with these two trading mechanisms, we examine their possible co-existence in the context of informal and formal markets. Other than having different trading protocols, we also consider other distinguishing features. We find a unique stable equilibrium where price-posting (formal markets) and bargaining (informal markets) co-exist. In a richer environment where both sellers and buyers can move across markets, we show that there exists a unique stable dynamic equilibrium where formal and informal activities also co-exist whenever sellers’ and buyers’ net costs of trading in the formal market have opposite signs.     

Explanatory factors for participation in formal standardisation processes: Empirical evidence at firm level

In contrast to the long tradition of empirical research into the innovation activities and R&D collaboration of companies, the issue of standardisation has been analysed mostly in theoretical approaches. This paper presents an empirical analysis of the participation of German companies in formal standards development organisations. It becomes clear that company size has a significant positive effect on the probability of a participation in standardisation. We focus further on two aspects, on R&D as input and export intensity as performance indicator, in order to explain the likelihood to join formal standardisation processes. Both the R&D intensity and the export activities exhibit an inverse U relationship. Obviously, even participating in standardisation processes requires a certain absorptive capacity, but R&D and export intensive companies expect more disadvantages, like unintended knowledge spill-overs, from joining formal standardisation processes and, therefore, stay away. In addition, export activities increase the likelihood to join formal standardisation processes up to a certain level, although companies with very high export shares expect less benefit from joining formal standardisation processes. Finally, some policy conclusions are derived.