Location in a congested city

This paper analyzes optimal location decisions in a city where both residential and employment locations are endogenously determined. A model is constructed which includes both traffic congestion among commuters and colocational externalities among firms. The model establishes that if location tax of the kind discussed by Koopmans and Beckman is imposed on both residential and employee locations, the private decisions of households and firms will produce an optimal pattern of location.     

The incidence of congestion and congestion tolls

In contrast with the enormous literature on efficiency aspects of congestion tolls, very little has appeared on their equity implications. Simulation is applied to a standard urban model to learn about the distributional aspects of an optimal toll, or the absence of one. Tolls are found to produce distributional changes which may overshadow their effects on allocative efficiency. In passing, the model is used to demonstrate that lagged supply adjustments to increases in the demand for suburban housing may be an effective, if second-best, alternative to congestion tolls.     

Policy Effects in Hyperbolic vs. Exponential Models of Consumption and Retirement

This paper constructs a structural retirement model with hyperbolic preferences and uses it to estimate the effect of several potential Social Security policy changes. Estimated effects of policies are compared using two models, one with hyperbolic preferences and one with standard exponential preferences. Sophisticated hyperbolic discounters may accumulate substantial amounts of wealth for retirement. We find it is frequently difficult to distinguish empirically between models with the two types of preferences on the basis of asset accumulation paths or consumption paths around the period of retirement. Simulations suggest that, despite the much higher initial time preference rate, individuals with hyperbolic preferences may actually value a real annuity more than individuals with exponential preferences who have accumulated roughly equal amounts of assets. This appears to be especially true for individuals with relatively high time preference rates or who have low assets for whatever reason. This affects the tradeoff between current benefits and future benefits on which many of the retirement incentives of the Social Security system rest.Simulations involving increasing the early entitlement age and increasing the delayed retirement credit do not show a great deal of difference whether exponential or hyperbolic preferences are used, but simulations for eliminating the earnings test show a non-trivially greater effect when exponential preferences are used.     

Political instability, investment and economic growth in Sub-Saharan Africa

This paper explores the relationship between political instabilityand economic growth in Sub-Saharan African nations. A more comprehensivemeasure of political instability than has previously been developedis used in combination with a simultaneous equations model anddynamic panel estimation approach to produce several interestinginferences. First, the statistically significant inverse relationshipbetween political instability and economic growth identifiedby earlier studies is confirmed by the estimates presented here.Second, the estimated system of equations indicates that economicgrowth and political instability are jointly endogenous. Third,in addition to the direct impact that political instabilityhas upon growth, estimates confirm the hypothesis that politicalinstability indirectly decreases economic growth by decreasinglong-run capital accumulation. Fourth, failure to account forthe dynamic nature of growth equations as well as the endogeneityof explanatory variables may produce biased effects of politicalinstability on growth. Fifth, the broad measure of politicalinstability we use in this study can better capture the effectsof political instability on economic growth than 'elite' instabilitythat has been used by earlier researchers. Finally, principalcomponents estimation is used to develop a measure of politicalinstability that can serve as an alternative to the arbitraryweighting scheme used in previous research.     

Fraud in Sustainability Departments? An Exploratory Study

While sustainability is largely associated with do-gooders, this article discusses whether and how fraud might also be an issue in sustainability departments. More specifically, transferring the concept of the fraud triangle to sustainability departments I discuss possible pressures/incentives, opportunities, and rationalizations/attitudes for sustainability managers to commit fraud. Based on interviews with sustainability and forensic practitioners, my findings suggest that sustainability managers face mounting pressure and have opportunities to manipulate due to an immature control environment. Whether a presumably morality-driven attitude may prevent them from committing and easily rationalizing fraud remains controversial. Even though cases of fraud happening in sustainability departments are still widely unknown, the interview analysis reveals that sustainability fraud is likely to occur at least to some extent—and presumably remains undetected. The study brings to light the importance of a clear commitment from executives to sustainability to prevent sustainability fraud and demonstrates adverse developments driven by external stakeholders, specifically the bonus relevancy of sustainability index scores. In particular, the study shows a lack of awareness for potential fraud in sustainability departments.