capital market segmentation and u s farm real estate pricing in this paper we present and test a segmented capital market equilibrium we extend the traditional capm by explicitly considering barriers to the flow of external equity capital into farm real estate markets the empirical results provide a plausible explanation as to why the traditional arbitrage based pricing models fail to explain equity pricing in farmland markets

identifying the efficiency status in network dea abstract data envelopment analysis dea is commonly employed to evaluate the efficiency performance of a decision making unit dmu that transforms exogenous inputs into final outputs in such a black box dea approach details of an internal production process of the dmu are typically ignored and hence the locations of inefficiency are not adequately provided in view of this dea researchers have recently developed various network approaches by looking into the black box where the inputs that enter the box and the outputs that come out of it are only considered however most of these network approaches evaluate divisional efficiency by using an optimal solution of their respective optimization problem if such an optimal solution is used in the case when there are multiple optima then managerial guidance based on this solution alone may be inappropriate because more appropriate targets from the viewpoint of management may be ignored taking this fact into account therefore we propose a network approach for identifying the efficiency status of each dmu and its divisions this approach provides a practical computational procedure

weak disposability in nonparametric production analysis reply to fare and grosskopf fare and grosskopf this issue claim that a single abatement factor suffices for modeling weak disposability in nonparametric production models and that the kuosmanen 2005 technology that uses multiple abatement factors is larger than necessary this article demonstrates by a numerical example that a single abatement factor does not suffice to capture all feasible production plans and that its use leads to the violation of convexity one of the maintained assumptions of the model we also prove that the kuosmanen technology is the correct minimum extrapolation technology under the stated axioms

degree of scale economies and congestion a unified dea approach abstract there are increasing concerns about how increase in congestion can adversely affect output as well as about the relative benefit cost ratio or return on investment associated with alternative projects or policies to address those problems regardless of what policy strategies are used to address congestion the fact remains that we cannot assess the economic benefits of congestion reduction strategies unless we are able to measure the extent to which congestion affects productivity in general and scale economies in particular this paper makes a novel attempt to suggest a method in a non parametric framework to measure scale elasticity in production in the presence of congestion

using generalized method of moments to test mean variance efficiency this paper develops tests of unconditional mean variance efflciency under weak distributional assumptions using a generalized method of moments framework these tests are potentially more robust than commonly employed tests which rely on the assumption that asset returns are normally distributed and temporarily i i d using returns for size based portfolios from 1926 to 1988 we show that the conclusion concerning the mean variance effilciency of market indexes can be sensitive to the test considered the application of multivariate statistical techniques in financial economics has become common practice in recent years much of the development has been in the area of testing asset pricing models the assumption that asset returns follow a time invariant multivariate normal distribution permits tests of restrictions on model parameters in a pooled time series cross section framework these tests can be interpreted as tests of the mean variance efficiency of a portfolio or combination of portfolios gibbons 1982 jobson and korkie 1982 stambaugh 1982 shanken 1985 1987 kandel and stambaugh 1987 mackinlay 1987 and gibbons ross and shanken 1989 are examples of work presenting multivariate tests of the capital asset pricing model connor and korajczyk 1988 and lehmann and modest 1988 present multivariate tests of the arbitrage pricing model breeden gibbons and litzenberger 1989 present multivariate tests of the consumption based capm although these papers assume the normality of asset returns little analysis has been conducted to understand the sensitivity of the inferences to violations of this assumption 2 3

the mean variance efficiency of benchmark portfolios uk evidence abstract this paper examines the ex ante mean variance efficiency of four alternative benchmark portfolios within a uk context each of the benchmark portfolios is shown to be mean variance inefficient over the period january 1980 to december 1989 additionally the gibbons et al test statistic of efficiency appears to be fairly robust to violations in the distributional assumptions gibbons m r s a ross and j shanken 1989 test of the efficiency of a given portfolio econometrica 57 1121 1152

productivity and customer satisfaction in swedish pharmacies a dea network model this paper presents a data envelopment analysis dea network model that allows inclusion of customer satisfaction in efficiency and productivity measures the network consists of a production node and a consumption node and offers flexibility in modelling the production and consumption process where a firm specific allocation of input resources to production and customer oriented activities is allowed the proposed model is applied on a sample of swedish pharmacies with organizational objectives that necessitates a monitoring of efficiency and productivity as well as customer satisfaction estimation results from the network model and a direct productivity model without customer satisfaction are compared and indicate that the technical efficiency is lower under the network model the productivity results indicate productivity progress under both models albeit with a slower rate of change under the network model

a comment on weak disposability in nonparametric production analysis in his 2005 paper in this journal kuosmanen argues that shephard s specification of weak disposability in activity analysis dea models is not correct we show that shephard s specification does satisfy weak disposability and is the smallest technology to do so

a multivariate linear regression test for the arbitrage pricing theory a test for the arbitrage pricing theory which employs a multivariate linear regression model is developed given a sample of return premiums for a set of n assets which includes a subset of k linearly independent portfolios the k factor apt hypothesis is accepted if the intercept term is zero in the multivariate regression of the n k returns on the k portfolios the test may be carried out simply by using univariate multiple regression software the relation of this test to the concept of performance potential and sharpe s measure of performance is also discussed if the performance potential of the k portfolios is not significantly less than the performance potential of the complete set of n assets then the k factor apt hypothesis is accepted in roll and ross rr 10 an empirical investigation of the ross 11 arbitrage theory of pricing apt was carried out the central core of the apt as outlined in rr is that the return generating process for a population of n assets is a linear function of only a few say k k n systematic factors or components and as a consequence many portfolios are close substitutes the central conclusion of the apt is that the mean premium return vector lies in a k dimensional subspace spanned by the factor loadings the purpose of the empirical investigation as claimed by rr was to investigate the existence of the factors and their association with the risk premia as stressed by rr their methodology does not determine k but is designed to test the hypothesis that there exist several factors whose factor loadings together explain a significant portion of the variation in the mean premium returns the empirical results in rr however indicate the presence of three to four priced factors the first empirical test outlined by rr involves two steps using time series data the mean return premium vector is estimated and a factor analysis procedure is used to estimate the k factors and their loadings a complex weighted least squares procedure is then used to estimate the linear model relating the mean return premium vector to the factor loadings the weighted least squares procedure requires estimation of the matrix of weights and is carried out for t 1 2 t cross sections in this paper the central conclusion of the apt is shown to be equivalent to a statement about the intercept term in the multivariate regression function of a

congestion measurement under different policy objectives an analysis of chinese industry abstract in recent years the economic performance of chinese industry has improved significantly however the congestion caused by excessive investment has plagued its sustainable development in order to make full use of resources it is necessary for the chinese government to measure industrial congestion from different perspectives however most studies for measuring congestion only consider desirable outputs even if in practice these are always accompanied by undesirable outputs in this paper three policy objectives are proposed for industrial development in china the economic priority the environmental priority and the economic and environmental win win three new data envelopment analysis dea models with undesirable outputs were built for measuring undesirable congestion desirable congestion and double congestion respectively for these policy objectives these approaches can not only identify congestion situation but also calculate the total amount of congestion and were applied to an analysis of the congestion of regional industries in china results show that most regions have some form of longstanding input congestion under different policy objectives with this resulting in serious waste of resources based on the results obtained some suggestions for sustainable industrial development in china are proposed

a note on the geometry of shanken s csr t2 test for mean variance efficiency abstract shanken 1985 derives a test for the zero beta capital asset pricing model capm which as he points out is equivalent to a test of the mean variance efficiency of the market portfolio this note illustrates the geometry of shanken s test in the mean variance space

a portfolio performance index fund managers may sensibly be averse to earning a time averaged portfolio return that is less than the average return of some designated benchmark when a portfolio is expected to earn a higher average return than the benchmark return the probability that it will not approaches zero asymptotically at a computable exponential decay rate the probability decay rate is thus proposed here as a new portfolio performance index in the widely analyzed special case in which returns are normally distributed the new performance index maximizing portfolio is the same as the popular sharpe ratio maximizing portfolio the results of the two approaches generally differ however because of nonnormal levels of skewness and or kurtosis in the portfolio attributable to large asymmetrical economic shocks or investments in options and other derivative securities an illustrative example will show that the new index is easy to implement and consistent with empirical evidence on portfolio choice favors investments with

multilateral productivity comparisons when some outputs are undesirable a nonparametric approach multilateral productivity comparisons of firms producing multiple outputs some of which are undesirable are obtained by making two modifications to the standard farrell approach to efficiency measurement the restriction that production technology satisfy strong disposability of outputs is relaxed to allow for the fact that undesirable outputs may be freely disposable and the efficiency measures are modified to allow for an asymmetric treatment of desirable and undesirable outputs performance measures that satisfy these requirements are calculated as solutions to programming problems the methodology is applied to a sample of mills producing paper and pollutants

dea congestion and returns to scale under an occurrence of multiple optimal projections abstract economic implications of congestion have been recently discussed in many dea data envelopment analysis studies in addition several previous research efforts have explored a theoretical linkage between returns to scale rts and the concept of congestion because the two economic concepts are closely connected to each other tone and sahoo tone k sahoo b k 2004 degree of scale economies and congestion a unified dea approach european journal of operational research 158 755 772 have published the theoretical linkage in this journal all of the previous studies including their research 2004 assume a unique optimal solution in the investigation on dea based congestion when multiple solutions occur in dea based congestion measurement the economic implications of congestion obtained from the previous research are all problematic from both theoretical and practical perspectives to deal with the issue this study explores how to deal with the occurrence of multiple solutions in the dea based congestion measurement this study proposes a new approach for the congestion measurement and theoretically compares the proposed approach with tone and sahoo 2004

dea radial measurement for environmental assessment and planning desirable procedures to evaluate fossil fuel power plants abstract energy policy depends on a proper use of methodology in guiding a large energy issue such as the global warming and climate change dea is one of such methodologies that are often used for preparing environmental policy which is closely linked to various energy issues unfortunately the use of dea applied to environmental policy is insufficient often misguiding policy makers and other individuals who are involved in energy issues this study provides three guidelines for a use of dea in preparing environmental assessment first it is important to prepare both primal and dual formulations to confirm whether information regarding all production factors i e inputs desirable and undesirable outputs is fully utilized in dea assessment second dea has model variations in radial and non radial measurements it is necessary for us to examine environmental issues by different models in order to avoid a methodological bias existing in those empirical studies finally dea environmental assessment needs to incorporate the concept of natural and managerial disposability the natural disposability indicates that a firm negatively adapts a regulation change on undesirable outputs in contrast the managerial disposability indicates that a firm positively adapts the regulation change because the firm considers the regulation change as a new business opportunity

potential performance and tests of portfolio efficiency abstract the potential performance of an asset set may be obtained by choosing the portfolio proportions to maximize the sharpe 1966 performance measure if a portfolio has a sharpe measure equivalent to the potential performance of the underlying set of assets then it is efficient multivariate statistical procedures for comparing potential performance and testing portfolio efficiency are developed and then evaluated using simulations two likelihood ratio statistics are then used to compare stock and bond indices against sets of 20 and 40 portfolios the procedures are also compared to the gibbons 1982 methodology for testing financial models

returns to scale and damages to scale under natural and managerial disposability strategy efficiency and competitiveness of petroleum firms environmental assessment recently becomes a major policy issue all over the world this study discusses how to use data environment analysis dea for environmental assessment for planning corporate strategy and international competitiveness an important feature of dea environmental assessment is that it classifies outputs into desirable good and undesirable bad outputs because all private and public entities produce not only desirable outputs but also undesirable outputs as a result of their production activities this study proposes the two types of output unification for dea environmental assessment by using a non radial model one of the two output unifications is that it considers a decrease in an input vector along with a decrease in the vector of undesirable outputs this type of unification is referred to as natural disposability the other unification considers an increase in an input vector but a decrease in the vector of undesirable outputs this type of strategy is referred to as managerial disposability both unifications increase the vector of desirable outputs after developing the two concepts on disposability this study theoretically explores how to measure returns to scale rts under natural disposability and damages to scale dts under managerial disposability to document the practicality of the proposed approach this study applies it to compare the performance of national oil firms with that of international oil companies this study identifies four important findings on the petroleum industry first national oil companies outperform international oil companies in the unified efficiency under natural disposability second international oil companies outperform national oil companies in the unified efficiency under managerial disposability third national oil firms exhibit a mixed result on rts while international oil firms exhibit decreasing rts finally both national and international oil companies exhibit increasing dts implying that all oil firms need to decrease their operational sizes for improving their environmental performance on co2 emission as an alternative strategy the result suggests that they need to introduce technology innovation e g clean air technology into their business operations the technology based strategy has more practicality than the size reduction in their operations

productivity and intermediate products a frontier approach abstract in recent years it has become popular to measure productivity using non parametric approaches however this has been done while ignoring intermediate products here we develop a non parametric productivity measure that explicitly incorporates such products

multivariate proxies and asset pricing relations abstract a framework is developed in which inferences can be made about the validity of an equilibrium asset pricing relation even though the central aggregate in this relation is unobservable a multivariate proxy for the true market portfolio consisting of an equal weighted stock index and a long term government bond index is employed in an investigation of the sharpe lintner capm the empirical evidence suggests that we can reject the joint hypothesis that a capm is valid and b multiple correlation between the true market portfolio and proxy assets exceeds 0 7 connections to the equilibrium factor pricing literature are also explored

congestion measurement in nonparametric analysis under the weakly disposable technology abstract congestion is a widely observed economic phenomenon where outputs are reduced due to excessive amount of inputs the previous approaches to identify congestion in nonparametric analysis only consider desirable outputs in the production process undesirable outputs are usually jointly produced with desirable outputs in this paper we propose an approach for measuring congestion in the presence of desirable and undesirable outputs simultaneously the proposed approach can discriminate between the congested dmus and the truly efficient dmus which are all efficient according to the scores calculated by the directional distance function finally an empirical example is used to illustrate the approach

productivity growth and pollution in state manufacturing the directional output distance function chambers chung fare 1996 is used to construct a malmquist luenberger index of total factor productivity growth for manufacturing when both good and bad outputs are jointly produced the index is constructed using information on good and bad output quantities and input quantities circumventing the problem of recovering shadow price information for the bad output needed for the fisher or tornqvist type of productivity indices accounting for toxic releases in manufacturing productivity growth averages 1 4 an nually during 1988 1994 the findings also suggest that the failure to account for toxic releases in manufacturing results in a significant under statement of total factor productivity growth

congestion and returns to scale in data envelopment analysis congestion indicates an economic state where inputs are overly invested evidence of congestion occurs whenever reducing some inputs can increase outputs return to scale is another related important economic implication of dea efficiencies in this research we discuss together the problems of congestion constant return to scale increasing return to scale and decreasing return to scale by output oriented dea models c2r model bc2 model fg model st model and a modified model we identify the necessary and sufficient conditions for the evidence of congestion constant increasing and decreasing returns to scale we show the exclusive relationships between the concepts of congestion and returns to scale numerical examples are provided for illustration

deriving the dea frontier for two stage processes data envelopment analysis dea is a method for measuring the efficiency of peer decision making units dmus recently dea has been extended to examine the efficiency of two stage processes where all the outputs from the first stage are intermediate measures that make up the inputs to the second stage the resulting two stage dea model provides not only an overall efficiency score for the entire process but as well yields an efficiency score for each of the individual stages due to the existence of intermediate measures the usual procedure of adjusting the inputs or outputs by the efficiency scores as in the standard dea approach does not necessarily yield a frontier projection the current paper develops an approach for determining the frontier points for inefficient dmus within the framework of two stage dea

currency hedging for international portfolios this paper examines the benefits from currency hedging both for speculative and risk minimization motives in international bond and equity portfolios the riskreturn performances of globally diversified portfolios are compared with and without forward contracts over the period 1974 to 1990 inclusion of forward contracts results in statistically significant improvements in the performance of unconditional portfolios containing bonds conditional strategies are also implemented both in sample and out of sample and are shown to both significantly improve the risk return tradeoff of global portfolios and to outperform unconditional hedging strategies whether international portfolios should be hedged against currency risks is the subject of an active debate the theoretical side of the debate has been closely associated with two strands in the academic literature international asset pricing and optimal hedging in the futures markets in the international asset pricing model iapm of solnik 1974 optimal portfolios contain positions in forward contracts or equivalently foreign currency denominated bills these positions which can differ from the positions in foreign stocks have since been termed hedges black 1990 shows that under additional assumptions the hedge ratios should be identical for all investors regardless of their nationality universality and that investors should never fully hedge their foreign currency exposures similarly theoretical models from the futures literature produce demands for hedging instruments that contain both speculative and hedging components the empirical issue unanswered so far is whether adding forward contracts to international portfolios significantly improves the risk return profile of global investments empirical research has barely begun to respond to the challenges of theoretical models there exists little empirical evidence on either the relevance of black s universal hedge ratios or the optimality of hedge ratios less than one instead researchers have concentrated on the benefits of fully hedging exchange risk for example eun and resnick 1988 indicate that stock portfolios perform better when fully hedged but offer no statistical tests

weak disposability in nonparametric production analysis with undesirable outputs environmental economics and natural resources group at wageningen university in the netherlands weak disposability of outputs means that firms can abate harmful emissions by decreasing the activity level modeling weak disposability in nonparametric production analysis has caused some confusion this article identifies a dilemma in these approaches conventional formulations implicitly and unintentionally assume all firms apply uniform abatement factors however it is usually cost effective to abate emissions in those firms where the marginal abatement costs are lowest this article presents a simple formulation of weak disposability that allows for non uniform abatement factors and preserves the linear structure of the model

alternative treatments of congestion in dea a rejoinder to cooper gu and li abstract this paper is a response to cooper w w b gu and s li comparisons and evaluations of alternative approaches to the treatment of congestion in dea european journal of operational research this issue who claim that the standard fgl procedure by fare grosskopf and lovell for dealing with congestion in dea can i fail to identify congestion when it is present and ii identify congestion when it is not present we clarify the notion of congestion and its relationship to structural efficiency and free disposability respectively to point out that the fgl approach was originally intended for measuring structural efficiency i e the influence of congestion on the efficiency of a particular production unit not for identifying occurrence of congestion in any feasible production vector moreover we point out that the result of cooper et al partially arises from ignorance of some key maintained assumptions underlying the fgl approach further we present some counter examples which demonstrate that the alternative approach advocated by cooper et al can equally fail in identification of congestion finally some remarks on the influence of sampling error and errors in variables on the two stage dea approaches are presented

currency hedging for international stock portfolios the usefulness of mean variance analysis abstract we test whether hedging currency risk improves the performance of international stock portfolios we show that an auxiliary regression provides a wealth of information about the optimal portfolio holdings for non mean variance investors analogous to the information provided by the jensen regression about optimal portfolio holdings for the mean variance case we find that static hedging with currency forwards does not lead to significant improvements in portfolio performance for a us dollar based stock portfolio from the g5 countries whereas dynamic hedges that are conditional on the interest rate spread do these conclusions hold for both mean variance and power utility investors and show up both in sample and out of sample however the optimal forward positions can differ significantly for both types of investors

comparisons and evaluations of alternative approaches to the treatment of congestion in dea abstract this paper examines the two approaches that are presently available in the data envelopment analysis dea literature for use in identifying and analyzing congestion the first approach due to fare et al fare r grosskopf s lovell c a k 1985 the measurement of efficiency of production kluwer nijhoff boston has been extensively employed to identify congestion in areas such as the provision of health services the latter approach due to cooper et al cooper w w thompson r g thrall r m 1996 annals of operations research 66 3 45 was subsequently extended by brockett et al brockett p l cooper w w shin h c wang y 1998 socio economic planning sciences 32 1 20 to treat tradeoff possibilities between employment and output in chinese production when congestion is present in contrast with cooper et al examples are provided in this paper which show that the fare et al approach can fail in both modes it can show congestion to be present when this is not consistent with the observed behavior it can also fail to exhibit congestion when the data show it to be present suggestions are offered both for i taking precautions before using the fgl approach and for ii overcoming these shortcomings