UPDATED:
20 June, 2008
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Robust Benefit Function Transfer: A Bayesian Model
Averaging Approach
(file size: 376K, last updated: 01/2007)
A Benefit Function Transfer obtains estimates of Willingness-to-Pay (WTP) for the evaluation of a given policy at a site by combining existing information from different study sites. This has the advantage that more efficient estimates are obtained, but it relies on the assumption that the heterogeneity between sites is appropriately captured in the Benefit Transfer model. A more expensive alternative to estimate WTP is to analyse only data from the policy site in question while ignoring information from other sites. We make use of the fact that these two choices can be viewed as a model selection problem and extend the set of models to allow for the hypothesis that the benefit function is only applicable to a subset of sites. We show how Bayesian Model Averaging (BMA) techniques can be used to optimally combine information from all models.
The Bayesian algorithm searches for the set of sites that can form the basis for estimating a Benefit function and reveals whether such information can be transferred to new sites for which only a small dataset is available. We illustrate the method with a sample of 42 forests from U.K. and Ireland. We find that BMA benefit function transfer produces reliable estimates and can increase about 8 times the information content of a small sample when the forest is 'poolable'.
Do childless households support local public provision of education
(file size: 310K, last updated: 01/2007)
Empirical and theoretical studies show that the local provision of public education affects the well being of individuals through two channels: the first reflects the direct use of the good, whereas the second runs through the value of the housing. The second effect leans on the idea that the quality of public education is capitalized into the value of the own housing.
Empirical evidence finds that in a multi-community model childless households support local public spending in education because of the capitalization effect. I study the behavior of childless households, not necessarily elderly, in a two community model and show that the capitalization effect may not be a sufficient condition for middle aged households without children to support local public spending in education by a majority voting.
Household-level Credit Constraints in Urban Ethiopia
(file size: 202K, last updated: 03/2007)
Empirical evidence on determinants of credit constraints and the amount borrowed by urban household in Sub-Saharan Africa is almost non-existent. Using an extended direct approach by virtue of the unique data set we have (the Fourth Round Ethiopian Urban Household Survey), we analysed the determinants of credit constraints and the amount borrowed by urban households. We find a high percentage of credit-constrained households, the majority of which constitute discouraged borrowers. Discrete choice models that control for potential endogeneity and selectivity bias have been fitted to our data. Our analysis shows current household resources, number of dependants, and location as significant correlates.
A Survey of the Effects of the Minimum Wage in Latin America
(file size: 255K, last updated: 03/2007)
The available empirical minimum wage literature, which is mostly based on US evidence, is not very useful for analyzing developing countries, where the minimum wage affects many more workers and labour institutions and law enforcement differ in important ways. The main contribution of this paper is to survey the existing minimum wage literature for Latin America.
[This paper is a reproduction of Chapter 1 of Lemos' doctorate thesis, available at the library collection of the University College London. This paper contains a survey of studies available until 2003.]
Financial Development, Openness and Institutions: Evidence from Panel Data
(file size: 362K, last updated: 05/2007)
Utilising four annual panel datasets and dynamic panel data estimation procedures we find that trade and financial openness, as well as economic institutions are statistically important determinants of the variation in financial development across countries and over time since the 1980s. However, we find mixed support for the hypothesis that the simultaneous opening of both trade and capital accounts is necessary to promote financial development in a contemporary setting.
Single Equation Models, Co-Integration and the Expectations Hypothesis of the Term Structure of Interest Rates
(file size: 1215K, last updated: 06/2007)
The purpose of this paper is twofold. First, by focusing on Single Equation and VECM techniques commonly employed to test for the Expectations Hypothesis of the Term Structure of interest rates (EHTS), it sheds light on the conditions - in terms of the different classes of stochastic processes of the spot and forward rates - that must hold for the EHTS to be valid. In doing so, the existing linkage between the two strands of literature is highlighted. Second, by using kalman filter and maximum likelihood, estimates of a permanent-transitory components model for spot and forward interest rates are carried out. The simple parametric model helps discern the relative contributions of both departures from rational expectation and time varying term premium to the invalidation of the EHTS. Departures from rational expectations turn out to have negligible impact on the rejection of the EHTS. Estimates of the time varying term premia for the short-end of the term structure spectrum are persistent and reasonable in magnitude, and exhibit sign fluctuations.
Group formation and governance
(file size: 310K, last updated: 06/2007)
This paper studies the impact of the governance of a group, whether be it unanimity, simple majority or qualified majority, on its size, composition, and inclination to change the status quo. Somewhat surprisingly, we show that not only unanimity might favor the formation of larger groups than majority, but also a change of status quo. This paper therefore suggests that unanimity, often blamed for the European inertia of the last two decades, was only a scapegoat.
Intellectual Property Disclosure as "Threat"
(file size: 209K, last updated: 08/2007)
This paper models the disclosure of knowledge as a "threat", useful in ensuring firms keep their commitments. We show that firms holding knowledge are better able to enforce agreements than firms that don’t. In markets requiring innovation to make a product, disclosure is a more powerful threat than entry by the punishing firm alone. Occasionally, the punishing firm won’t be able to innovate, making it impossible for it to enter the cheating firm’s market and punish. The punishing firm, however, can through disclosure credibly ensure that one, if not many, firms enter the cheating firm’s market. In the model, firms contract explicitly to exchange knowledge and tacitly to coordinate the introduction of innovations to the marketplace. We find conditions under which firms can self-enforce both agreements. The enforcement conditions are weaker when (1) firms possess knowledge and (2) knowledge is easily transferable to other firms. The disclosure threat has implication for antitrust law generally, which are considered.
Explaining the anomalies of the exponential discounted utility model
(file size: 238K, last updated: 09/2007)
In a major contribution, Loewenstein and Prelec (1992) (LP) set the foundations for the behavioral approach to decision making over time. We show that the LP theory is incompatible with two very useful classes of value functions: the HARA class and the constant loss aversion class. Resultingly, the LP theory has been used infrequently in applications, which have largely used the ß, δ form of hyperbolic preferences. We propose a more general but equally tractable class of utility functions, the simple increasing elasticity (SIE) class, which is compatible with constant loss aversion in a reformulated version of LP. Allowing for reference dependence and different discount rates for gains and losses the SIE class is able to explain impatience, gain-loss asymmetry, magnitude effect, and the delay-speedup asymmetry even under exponential discounting. If combined instead with the (reformulated) LP theory, the SIE class in addition can also explain the common difference effect.
Optimal income taxation in the presence of tax evasion: Expected utility versus prospect theory
(file size: 347K, last updated: 09/2007)
The predictions of expected utility theory (EUT) applied to tax evasion are flawed on two counts: (i) They are quantitatively in error by huge orders of magnitude. (ii) Higher taxation is predicted to lower evasion, which is at variance with the evidence. An emerging literature in behavioral economics, most notably based on prospect theory (PT), has shown that behavioral economics is much better at explaining tax evasion. We extend this literature to incorporate issues of optimal taxation. As a benchmark for a successful theory, we require that it should explain, jointly, the facts on the tax rate, tax gap and the level of government expenditure. We find that when taxpayers use EUT (respectively, PT) and the optimal tax is derived from a social welfare function that also uses EUT (respectively, PT), then, the calibration results are completely at odds with the facts. However, when taxpayers use PT but the social welfare function uses standard EUT, there is a very close match between the predictions and the facts. This has important implications for context dependent preferences but also for the newly emerging literature on liberalism versus paternalism in behavioral economics.
Bayesian Analysis of Deterministic Time Trend and Changes in Persistence Using a Generalised Stochastic Unit Root Model
(file size: 859K, last updated: 10/2007)
This paper makes use of the novel Generalized Stochastic Unit Root (GSTUR) model, Bayesian model estimation and model comparison techniques to investigate the presence of a deterministic time trend in economic series. The model is specified to allow for changes in persistence over time, such as shifts from stationarity I(0) to nonstationarity I(1) or vice versa. This uncertainty raises the crucial question about how sure one can be that an economic time series has a deterministic trend when there is a change in the underlying properties. Empirical analysis indicates that the GSTUR model could provide new insights on time series studies.
Vertical integration and product innovation
(file size: 405K, last updated: 10/2007)
We study vertical integration and product innovation (in the form of horizontal product differentiation) as interdependent strategic choices of vertically related firms. We consider product innovation in the downstream market as a strategic decision of innovative firms facing a threat of vertical integration and market foreclosure by an upstream monopolist. Our main finding is that, although product differentiation allows to soften product market competition and to avoid market foreclosure, the downstream market may prefer less product differentiation to deter vertical integration. Therefore, less product innovation can be a possible social cost of a lenient antitrust policy.
Increasing elasticity of the value function in the Loewenstein-Prelec theory of intertemporal choice
(file size: 139K, last updated: 10/2007)
In a critique of the Loewenstein and Prelec (1992) theory of intertemporal choice, al-Nowaihi and Dhami (2006) point out to four errors. One of the alleged errors was that the value function in prospect theory is decreasing. But it is in fact increasing. We provide a correction and a formal proof. As a corollary, we show that the elasticity of the value function is bounded between zero and one. Nevertheless, all the remaining points in al-Nowaihi and Dhami (2006) remain valid.
Health Expenditure and Income in the United States
(file size: 245K, last updated: 10/2007)
This paper investigates the long-run economic relationship between health care expenditure and income in the US at a State level. Using a panel of 49 US States followed over the period 1980-2004, we study the non-stationarity and cointegration between health spending and income, ultimately measuring income elasticity of health care. The tests we adopt allow us to explicitly control for cross-section dependence and unobserved heterogeneity. Specifically, in our regression equations we assume that the error is the sum of a multifactor structure and a spatial autoregressive process, which capture global shocks and local spill overs in health expenditure. Our results suggest that health care is a necessity rather than a luxury, with an elasticity much smaller than that estimated in other US studies. Further, we observe a significant spatial spill over, though with a smaller intensity than that detected in other studies on spatial concentration of US health spending. Our broad perspective of cross section dependence as well as the methods used to capture it give new insights on the debate over the relationship between health spending and income.
Alice Through the Looking Glass: Strategic Monetary and Fiscal Policy Interaction in a Liquidity Trap
(file size: 369K, last updated: 10/2007)
The recent experience with low inflation has reopened interest in the liquidity trap; which occurs when the nominal interest rate reaches its zero lower bound. To reduce the real interest rate, and to stimulate the economy, the modern literature highlights the role of high inflationary expectations. Using the Dixit-Lambertini (2003) framework of strategic policy interaction, we find that the optimal institutional response to the possibility of a liquidity trap has two main components. First, an optimal inflation target given to the Central Bank. Second, the Treasury, who retains control over fiscal policy and acts as leader, is given optimal output and inflation targets. This keeps inflationary expectations sufficiently high and achieves the optimal rational expectations pre-commitment solution. Simulations show that this arrangement is (1) optimal even when the Treasury has no inflation target but follow's the optimal output target and (2) 'near optimal' even when the Treasury follows its own agenda through a suboptimal output target but is willing to follow an optimal inflation target. Finally, if monetary policy is delegated to an independent central bank with an optimal inflation target, but the Treasury retains discretion over fiscal policy, then the outcome can be a very poor one.
Existence of a Condorcet winner when voters have other-regarding preferences
(file size: 236K, last updated: 06/2008)
In standard political economy models, voters are 'self-interested' i.e. care only about 'own' utility. However, the emerging evidence indicates that voters often have 'other-regarding preferences' (ORP), i.e., in deciding among alternative policies voters care about their payoffs relative to others. We extend a widely used general equilibrium framework in political economy to allow for voters with ORP, as in Fehr-Schmidt (1999). In line with the evidence, these preferences allow voters to exhibit 'envy' and 'altruism', in addition to the standard concern for 'own utility'. We give sufficient conditions for the existence of a Condorcet winner when voters have ORP. This could open the way for an incorporation of ORP in a variety of political economy models. Furthermore, as a corollary, we give more general conditions for the existence of a Condorcet winner when voters have purely selfish preferences.
Investigating Economic Trends And Cycles
(file size: 429K, last updated: 04/2008)
Methods are described for extracting the trend from an economic data sequence and for isolating the cycles that surround it. The latter often consist of a business cycle of variable duration and a perennial seasonal cycle.
There is no evident point in the frequency spectrum where the trend ends and the business cycle begins. Therefore, unless it can be represented by a simple analytic function, such as an exponential growth path, there is bound to be a degree of arbitrariness in the definition of the trend.
The business cycle, however defined, is liable to have an upper limit to its frequency range that falls short of the Nyquist frequency, which is the maximum observable frequency in sampled data. This must be taken into account in fitting an ARMA model to the detrended data.