Economics - Research Publications

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    Gibbs samplers for a set of seemingly unrelated regressions
    Griffiths, W. E. ; Valenzuela, Ma. Rebecca ( 2004-08)
    Bayesian estimation of a collection of seemingly unrelated regressions, referred to asa ‘set of seemingly unrelated regressions’ is considered. The collection of seeminglyunrelated regressions is linked by common coefficients and/or a common errorcovariance matrix. Gibbs samplers useful for estimating posterior quantities aredescribed and applied to two examples – a set of linear expenditure functions and acost function and share equations from production theory.
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    Estimating and Combining National IncomeDistributions using Limited Data
    Chotikapanich, Duangkamon ; Griffiths, William E. ; Rao, D. S. Prasada ( 2005-02)
    A major problem encountered in studies of income inequality at regional and globallevels is the estimation of income distributions from data that are in a summary form.In this paper we estimate national and regional income distributions within a generalframework that relaxes the assumption of constant income within groups. A techniqueto estimate the parameters of a beta-2 distribution using grouped data is proposed.Regional income distribution is modelled using a mixture of country-specificdistributions and its properties are examined. The techniques are used to analysenational and regional inequality trends for eight East Asian countries and twobenchmark years, 1988 and 1993.
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    Survival on the Titantic: Illustrating Waldand LM Tests for Proportions and Logits
    DIXON, ROBERT ; GRIFFITHS, WILLIAM ( 2006-06)
    Students are very interested in lecture examples and class exercisesinvolving data connected to the maiden voyage and the sinking of the liner Titanic.Information on the passengers and their fate can be used to explore relationshipsbetween various tests for differences in survival rates between different groups ofpassengers. Among the concepts examined are tests for differences of proportionsusing a normal distribution, a chi-square test for independence, a test for the equalityof two logits and a test for the significance of the coefficient of a binary variable inlogit model. The relationship between Wald and LM test statistics is also examined.Two related examples are given, one to be used for step by step instructional purposesand one to be given as an exercise to students.
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    Bayesian Assessment of Lorenz andStochastic Dominance in Income Distributions
    Chotikapanich, Duangkamon ; GRIFFITHS, WILLIAM ( 2006-02)
    Hypothesis tests for dominance in income distributions has received considerableattention in recent literature. See, for example, Barrett and Donald (2003), Davidsonand Duclos (2000) and references therein. Such tests are useful for assessing progresstowards eliminating poverty and for evaluating the effectiveness of various policyinitiatives directed towards welfare improvement. To date the focus in the literaturehas been on sampling theory tests. Such tests can be set up in various ways, withdominance as the null or alternative hypothesis, and with dominance in eitherdirection (X dominates Y or Y dominates X). The result of a test is expressed asrejection of, or failure to reject, a null hypothesis. In this paper we develop and applyBayesian methods of inference to problems of Lorenz and stochastic dominance. Theresult from a comparison of two income distributions is reported in terms of theposterior probabilities for each of the three possible outcomes: (a) X dominates Y, (b)Y dominates X, and (c) neither X nor Y is dominant. Reporting results about uncertainoutcomes in terms of probabilities has the advantage of being more informative than asimple reject / do-not-reject outcome. Whether a probability is sufficiently high or lowfor a policy maker to take a particular action is then a decision for that policy maker.The methodology is applied to data for Canada from the Family Expenditure Surveyfor the years 1978 and 1986. We assess the likelihood of dominance from one timeperiod to the next. Two alternative assumptions are made about the incomedistributions –Dagum and Singh-Maddala – and in each case the posterior probabilityof dominance is given by the proportion of times a relevant parameter inequality issatisfied by the posterior observations generated by Markov chain Monte Carlo.
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    Estimating and combining national income distributions using limited data
    Chotikapanich, D ; Griffiths, WE ; Rao, DSP (TAYLOR & FRANCIS INC, 2007-01)
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    Estimating state-contingent production frontiers
    O'Donnell, CJ ; Griffiths, WE (WILEY, 2006-02)
    Chambers and Quiggin (2000) use state‐contingent representations of risky production technologies to establish important theoretical results concerning producer behavior under uncertainty. Unfortunately, perceived problems in the estimation of state‐contingent models have limited the usefulness of the approach in policy formulation. We show that fixed and random effects state‐contingent production frontiers can be conveniently estimated in a finite mixtures framework. An empirical example is provided. Compared to conventional estimation approaches, we find that estimating production frontiers in a state‐contingent framework produces significantly different estimates of elasticities, firm technical efficiencies, and other quantities of economic interest.