structural interpretation of vector autoregressions with incomplete identification revisiting the role of oil supply and demand shocks traditional approaches to structural vector autoregressions vars can be viewed as special cases of bayesian inference arising from very strong prior beliefs these methods can be generalized with a less restrictive formulation that incorporates uncertainty about the identifying assumptions themselves we use this approach to revisit the importance of shocks to oil supply and demand supply disruptions turn out to be a bigger factor in historical oil price movements and inventory accumulation a smaller factor than implied by earlier estimates supply shocks lead to a reduction in global economic activity after a significant lag whereas shocks to oil demand do not

marginal rate of transformation and rate of substitution measured by dea environmental assessment comparison among european and north american nations this study discusses the new use of dea data envelopment analysis environmental assessment to measure mrt marginal rate of transformation and rs rate of substitution among production factors e g inputs desirable and undesirable outputs to measure the degree on mrt and rs this study first examines a concept of disposability from the perspective of economic strategies to combat various environmental issues the strategies are extendable to a policy change for pollution prevention the underlying concept is separated into natural and managerial disposability under managerial disposability it is possible for us to measure an occurrence of desirable congestion or eco technology innovation considering the disposability concept this study discusses how to measure the type and magnitude of mrt and rs a problem of the mrt rs measurement is that these measures usually become unstable e g very large or small in these magnitudes because dea does not assume any functional form for economic activities to overcome such a difficulty this study equips dea environmental assessment with multiplier restriction by utilizing a unique feature on a proposed data treatment the multiplier restriction in dea has been never explored in previous works on environmental assessment in an application this study finds three important economic concerns on europe and north america first western europe outperforms eastern europe and north america in their unified efficiency measures under managerial disposability this study statistically confirms a difference between western and eastern europe but not between western europe and north america this result exhibits that eastern europe is not yet well developed at the level of the other two regions second eastern europe has exhibited mrt estimates that are different from western europe and north america the nations in eastern europe have an economic potential for industrial developments because the level of their industrial pollutions is less than that of the other two regions the potential is also found in their mrt estimates finally an interesting difference can be found in the rs estimate between eastern europe and western europe from 2008 to 2012 they have statistically exhibited a difference between the two regimes but not with north america this is because most nations in both western europe and north america have already attained a high level of economic successes so that they have a limited industrial potential under current production technology and eco technology the situation of the two regions will be changed along with new technology development in contrast eastern europe is different from the other two regions in terms of attaining such a level of social sustainability because of limited capital accumulation and limited opportunity for technology innovation

tariff based incentives for improving coal power plant efficiencies in india improving the efficiency of coal based power plants plays an important role in improving the performance of india s power sector it allows for increased consumer benefits through cost reduction while enhancing energy security and helping reduce local and global pollution through more efficient coal use a focus on supply side efficiency also complements other ongoing efforts on end use efficiency the recent restructuring of the indian electricity sector offers an important route to improving power plant efficiency through regulatory mechanisms that allow for an independent tariff setting process for bulk purchases of electricity from generators current tariffs based on normative benchmarks for performance norms are hobbled by information asymmetry where regulators do not have access to detailed performance data hence we propose a new incentive scheme that gets around the asymmetry problem by setting performance benchmarks based on actual efficiency data rather than on a normative basis the scheme provides direct tariff based incentives for efficiency improvements while benefiting consumers by reducing electricity costs in the long run this proposal might also be useful for regulators in other countries to incorporate similar incentives for efficiency improvement in power generation

religious participation and children s education a social capital approach abstract based on the argument in both economic and sociological literature that religion is conducive to children s human capital formation this paper provides a model of religious participation and explores a mechanism that social capital affects children s education a la coleman coleman j s 1988 social capital in the creation of human capital american journal of sociology 94 s95 s120 the model generates several interesting implications which help explain some important stylized facts about education and religion further in a dynamic setting the model shows that there exists a steady state in which individuals allocate a positive amount of time and resources to religious activities thus it complements the existing literature to explain why seemingly unproductive religions can be everlasting

relative performance of public and private ownership under yardstick competition electricity retail distribution abstract this paper focuses on productive efficiency in swedish retail electricity distribution during 1970 1990 using hedonic output s constructed from physical outputs and their qualities and network characteristics the main focus is on efficiency of privately owned municipal utilities municipal companies and companies with mixed ownerships three different approaches are used to examine whether ownership of the distribution companies has any systematic impact on the above issues we also examine returns to scale and technical change empirical results from the three alternative approaches show that privately owned companies are relatively more efficient we find evidence of scale economies and technical progress

forward curves scarcity and price volatility in oil and natural gas markets the role of inventory in explaining the shape of the forward curve and spot price volatility in commodity markets is central in the theory of storage developed by kaldor kaldor n 1939 speculation and economic stability the review of economic studies 7 1 27 and working working h 1949 the theory of the price of storage american economic review 39 1254 1262 and has since been documented in a vast body of financial literature including the reference paper by fama and french fama e f and k r french 1987 commodity futures prices some evidence on forecast power premiums and the theory of storage journal of business 60 55 73 on metals the goal of this paper is twofold i validate in the case of oil and natural gas the use of the slope of the forward curve as a proxy for inventory the slope being defined in a way that filters out seasonality ii analyze directly for these two major commodities the relationship between inventory and price volatility in agreement with the theory of storage we find that i the negative correlation between price volatility and inventory is globally significant for crude oil ii this negative correlation prevails only during those periods of scarcity when the inventory is below the historical average and increases importantly during the winter periods for natural gas our results are illustrated by the analysis of a 15 year database of us oil and natural gas prices and inventory

dynamic steam coal market integration evidence from rolling cointegration analysis abstract the aim of the paper is twofold first to assess the dynamics of the integration process of the international steam coal prices and second to investigate the changes in the roles of particular coal prices in this market in the light of changes in the structure of supply and demand the analysis is based on steam coal prices set by the largest world exporters and importers on both the atlantic and the pacific markets we use weekly data spanning from october 5 2001 to march 28 2014 the aim is achieved in two stages during the first one we use the rolling trace test to identify the integration of the steam coal market and during the second one we apply the rolling weak exogeneity test to determine the roles of the participants of the international steam coal market namely price setters and price takers our main findings can be summarized in two observations firstly the main world steam coal prices are integrated and during the period when freight costs are higher the coal market integration is weaker and when the costs are lower the integration is stronger secondly the role of particular coal prices is not stable in time generally price setters appear in the market which covers greater shares in the physical coal trade although indonesia and russia have a great share in the global export their prices remain price takers during the whole period as a consequence although russia remains the largest coal exporter of the steam coal to the european market it cannot dictate its prices in this market

energy consumption prices and economic growth in three ssa countries a comparative study in this paper we examine the causal relationship between energy consumption and economic growth in three sub saharan african countries namely south africa kenya and congo drc we incorporate prices as an intermittent variable in a bivariate setting between energy consumption and economic growth thereby creating a simple trivariate framework using the ardl bounds testing procedure we find that the causality between energy consumption and economic growth varies significantly across the countries under study the results show that for south africa and kenya there is a unidirectional causal flow from energy consumption to economic growth however for congo drc it is economic growth that drives energy consumption these findings have important policy implications insofar as energy conservation policies are concerned in the case of congo drc for example the implementation of energy conservation policies may not significantly affect economic growth because the country s economy is not entirely energy dependent however for south africa and kenya there is a need for more energy supply augmentations in order to cope with the long run energy demand in the short run however the two countries should explore more efficient and cost effective sources of energy in order to address the energy dependency problem

the impact of the north american shale gas revolution on regional natural gas markets evidence from the regime switching model this paper investigates the impact of the north american shale gas revolution on price movement regimes in the north american and european gas markets using the markov regime switching model it then measures price spreads between oil and gas from 1998 to 2015 to identify the impact of the revolution on the relationship between oil and regional gas prices the results show that the typical movement regime of henry hub prices changes from slightly upward to sharply downward in addition the clear seasonal effect of henry hub prices has disappeared after the shale gas revolution the typical movement of national balancing point nbp prices has changed gradually from a sharply upward regime to the alternative regimes between sharply downward and slightly upward tending to follow oil prices this indicates that the shale gas revolution has had little impact on nbp price movement meanwhile henry hub prices have decoupled from wti prices while nbp and brent prices have continued to exhibit a long term equilibrium level around which they have swung in the short time frame since the shale gas revolution pertinent energy policy makers and energy market participants should pay attention to these changes and adjust their trade production and investment strategies accordingly

what drives volatility in natural gas prices abstract we examine the primary drivers of u s natural gas price volatility to do so we apply a structural heterogeneous autoregressive var shvar model accommodating structural breaks in both the coefficient and volatility to monthly time series data on natural gas supply demand and price between january 1978 and july 2018 we detect several structural changes in coefficients and shock volatility in the natural gas market our findings indicate that the response of natural gas prices differs significantly depending on the regime and type of shock in the natural gas market while demand shocks specific to the natural gas market are the primary drivers of natural gas price volatility structural supply shocks also play a significant role in explaining movements in natural gas prices our results suggest that failure to consider structural breaks in the coefficient and volatility may result in biased estimates and distorted impulse responses of the impact of shocks on natural gas price volatility

set identification in models with multiple equilibria we propose a computationally feasible way of deriving the identified features of models with multiple equilibria in pure or mixed strategies it is shown that in the case of shapley regular normal form games the identified set is characterized by the inclusion of the true data distribution within the core of a choquet capacity which is interpreted as the generalized likelihood of the model in turn this inclusion is characterized by a finite set of inequalities and efficient and easily implementable combinatorial methods are described to check them in all normal form games the identified set is characterized in terms of the value of a submodular or convex optimization program efficient algorithms are then given and compared to check inclusion of a parameter in this identified set the latter are illustrated with family bargaining games and oligopoly entry games copyright 2011 oxford university press

divergence in technical efficiency of electric utilities evidence from the sapp abstract this paper investigates the convergence pattern of technical efficiency of the south africa power pool sapp utilities over the period april 2003 march 2010 by means of parametric and non parametric techniques technical efficiency scores are computed via both stochastic frontier analysis and data envelopment analysis mixed results are obtained from the neoclassical convergence approaches in addition distribution dynamics methods reveal some evidence of club formation and this result is supported with the occurrence of divergence taken as a whole technical efficiency is found to diverge among the utilities operating in the power pool

peers at work we study peer effects in the workplace specifically we investigate whether how and why the productivity of a worker depends on the productivity of coworkers in the same team using high frequency data on worker productivity from a large supermarket chain we find strong evidence of positive productiv ity spillovers from the introduction of highly productive personnel into a shift worker effort is positively related to the productivity of workers who see him but not workers who do not see him additionally workers respond more to the presence of coworkers with whom they frequently interact we conclude that social pressure can partially internalize free riding externalities that are built into many workplaces jel j24 l81 m54

understanding the us natural gas market a markov switching var approach abstract over the past three decades the us natural gas market has witnessed significant changes utilizing a standard bayesian model comparison method this paper formally determines four regimes existing in the market it then employs a markov switching vector autoregressive model to investigate the regime dependent responses of the market to its fundamental shocks the results reveal that the us natural gas market tends to be much more sensitive to shocks occurring in regimes existing after the decontrol act 1989 than the other regimes the paper also finds that shocks to the natural gas demand and price have negligible effects on natural gas production while the price of natural gas is mainly driven by specific demand shocks augmenting the model by incorporating the price of crude oil the results show that the impacts of oil price shocks on natural gas prices are relatively small and regime dependent

crime and social interactions the high variance of crime rates across time and space is one of the oldest puzzles in the social sciences this variance appears too high to be explained by changes in the exogenous costs and benefits of crime we present a model where social interactions create enough covariance across individuals to explain the high cross city variance of crime rates this model provides an index of social interactions which suggests that the amount of social interactions is highest in petty crimes moderate in more serious crimes and almost negligible in murder and rape

integration of physical and futures prices in the us natural gas market this paper examines the integration between the prices of different types of physical upstream end use and futures contracts of natural gas in the us for the period of june 1990 dec 2014 to examine the equilibrium relationship between physical and futures prices several cointegration tests are applied the study finds that a futures prices are cointegrated with wellhead power industrial and citygate prices b ng1 futures prices granger cause all physical prices c upstream physical prices granger cause futures prices d shocks to wellhead prices are the only ones among physical prices with persistent long term effects e shocks to futures prices have persistent effects on all physical prices f futures contracts with a longer time to maturity explain a larger portion of commercial gas price variations and g commercial and residential prices show different behavior compared to other physical prices in multiple tests

turbulent times uncovering the origins of us natural gas price fluctuations since deregulation abstract in this paper we investigate supply and demand shocks in the u s natural gas market focusing on how the effects of these shocks have changed over time using a sign identified structural vector autoregression svar model that allows for both time varying parameters and stochastic volatility we find that supply and demand shocks are the main drivers of natural gas price fluctuations during 1993 2015 with speculative activities playing a minor role during a portion of the sample period we also find that after the recent shale boom the supply and demand of natural gas in the us have become somewhat more elastic an examination of several volatile episodes during the sample period suggest that though natural gas price fluctuations are predominately determined by fundamental factors supply and demand shocks have significantly evolved over time

understanding regression versus variance tests for social interactions this article considers the relationship between the use of regressions and the use of variance contrast methods to uncover social interactions we illustrate how these methods employ different identifying assumptions and are therefore complementary approaches we also provide formal identification results that extend existing ones for the two methods jel c12 c21 c23 z13 this article is designed to understand the relationshipbetweentwoapproachestotheempirical analysis of social interactions the first approach is the use of linear regressions to uncover social interactions this approach estimates social interaction effects through changes in the conditional linear expectation of individual outcomes when group level variables are included in the conditioning set in econometrics this method was first analyzed by manski 1993 who dubbed it the linearin means model since the group level variables are typically averages of individual variables within the group this model is also studied by brock and durlauf 2001a 2001b cohencole 2006 and graham and hahn 2005 among others durlauf 2004 surveyed empirical studiesof social interactionsbasedonsuch regressions the second approach originally proposed by glaeser sacerdote and scheinkman 1996 and developed into a full inferential procedure by graham 2005 who refers to this approachasvariancecontrasts usesintragroup variation in behavior to infer social interactions the idea in this approach is that social interactions willinduceintragroupdependences in behavior that affect sample variances for intragroup outcomes there has been relatively little work evaluating social interactions using variance contrasts one reason is that with the exception of graham s work there is little formal statistical theory for the approach the purpose of this article was to clarify the relationship between regression and variance contrast tests weclarify how these tests employ different informational assumptions to achieve identification of social interaction specifically we argue that regression and variance contrast approaches correspond to identification via exclusion restrictions in the one case and covariance restrictions on errors in the other as such the two approaches replicate the classes of identification strategies that appear in the classical simultaneous equations literature see fisher 1966 for a classic treatment the remainder of the article is organized as

the population problem theory and evidence this study is concerned with the relationships among population growth poverty and environmental degradation with particular focus on the situation in developing countries the author rejects the concept of a general theory of fertility behavior in favor of an interpretation of these relationships which might be applicable to certain situations in the poorest parts of the indian subcontinent and sub saharan africa such situations include unacceptable risks of maternal death for poor illiterate women and a condemnation to extreme poverty in conditions of the deterioration of local resources and of the environment the author concludes that population growth rates are too high in certain specific areas and that an appropriate policy reaction to such conditions would be to try to change the options that men and women face so that their reasoned choice would be to lower their fertility

spatial externalities in agriculture empirical analysis statistical identification and policy implications summary spatial externalities can affect economic welfare and landscape pattern by linking farm returns on adjoining parcels of land while policy can be informed by research that documents spatial externalities statistically quantifying the presence of externalities from landscape pattern is insufficient for policy guidance unless the underlying cause of the externality can be identified as positive or negative this article provides a springboard for empirical research by examining the underlying structure social environmental interactions and statistical identification strategies for the analysis and the quantification of agricultural spatial externalities that are derived from observations of landscape change the potential for original policy treatments of agricultural spatial externalities in development and environment outcomes is highlighted

total factor energy efficiency of regions in china abstract this paper analyzes energy efficiencies of 29 administrative regions in china for the period 1995 2002 with a newly introduced index most existing studies of regional productivity and efficiency neglect energy inputs we use the data envelopment analysis dea to find the target energy input of each region in china at each particular year the index of total factor energy efficiency tfee then divides the target energy input by the actual energy input in our dea model labor capital stock energy consumption and total sown area of farm crops used as a proxy of biomass energy are the four inputs and real gdp is the single output the conventional energy productivity ratio regarded as a partial factor energy efficiency index is computed for comparison in contrast to tfee our index is found fitting better to the real case according to the tfee index rankings the central area of china has the worst energy efficiency and its total adjustmentof energy consumption amount is over half of china s total regional tfee in china generally improved during the research period except for the western area a u shape relation between the area s tfee and per capita income in the areas of china is found confirming the scenario that energy efficiency eventually improves with economic growth

discrete choice with social interactions this paper provides an analysis of aggregate behavioural outcomes when individual utility exhibits social interaction effects we study generalized logistic models of individual choice which incorporate terms reflecting the desire of individuals to conform to the behaviour of others in an environment of noncooperative decisionmaking laws of large numbers are generated in such environments multiplicity of equilibria in these models which are equivalent to the existence of multiple self consistent means for average choice behaviour will exist when the social interactions exceed a particular threshold local stability of these multiple equilibria is also studied the properties of the noncooperative economy are contrasted with the properties of an economy in which a social planner determines the set of individual choices finally a likelihood function based on the theoretical model is given and conditions for the econometric identifiability of the model are established

privatization technical efficiency and welfare consequences the case of the cote d ivoire electricity company cie abstract in 1990 cote d ivoire privatized the management of its electric power company lease contracting in this paper we are interested in identifying the economic effect of this institutional change by estimating a stochastic production frontier we have found that productive efficiency improved after privatization thanks to organizational innovations total factor productivity gains have been closely associated with a cost reduction strategy the way these gains have been distributed in a monopoly context suggests that consumers have been the main beneficiaries through a significant decrease of the relative price of electricity

natural gas from shortages to abundance in the united states abstract the history of natural gas wellhead and pipeline regulation deregulation and regulatory reforms are discussed these reforms brought natural gas shortages and pipeline inefficiencies to an end they also created an economic platform that could support unanticipated developments in the supply and costs of domestic natural gas such unanticipated developments emerged in the last few years as several technological innovations came together to make it commercially attractive to development us shale gas deposits located deep in the earth how and why shale gas supplies will lead to dramatic changes in the united states energy future with appropriate environmental regulatory reforms are discussed

methodological comparison among radial non radial and intermediate approaches for dea environmental assessment abstract this study compares three dea approaches for environmental assessment all of which are designed to examine the level of simultaneous achievement on economic prosperity and environmental protection so measuring the degree of sustainability development dea standing for data envelopment analysis has been widely applied for performance assessment in the past five decades a new type of applications is referred to as dea environmental assessment and it measures the performance of many organizations that utilize inputs to produce not only desirable outputs e g electricity but also undesirable outputs e g co 2 in the previous studies dea based performance evaluation for environment assessment is methodologically classified into radial or non radial category recently a new intermediate approach analytically locating between the radial and non radial measures has been proposed as the third alternative a use of the intermediate approach has several unique features all of which cannot be found in the radial and non radial ones the new approach measures the degree of unified inefficiency on each production factor and determines the level of total unified inefficiency from the average of the sum of these inefficiency scores this study discusses the analytical features by comparing the intermediate approach with the radial and non radial ones the methodological comparison attempts to convey a message that dea is indeed an important methodology but not perfect rather it is an approximation approach to examine the performance of various organizations many dea applications on energy and environment often suffer from a methodological bias implying that different approaches produce different empirical results thus in guiding a large policy issue such as the global warming and climate change it is necessary for us to compare several different approaches e g models and concepts to derive a reliable empirical suggestion the importance of such a message is applicable to not only dea but also the other types of empirical research in natural and social sciences therefore this study discusses the methodological bias issue from the practicality of the three dea approaches in assessing various concerns on energy and environment

dynamic instability of a mixed city in the presence of neighborhood externalities it has been often asked whether a city currently accommodating a variety of economic social and racial groups will continue to be a mixed city or will become exclusively occupied by a single group particularly poor blacks with all other groups moving out of the city in the long run in order to answer this question properly it seems essential to develop a long run dynamic model of a city with emphasis on socioeconomic factors like neighborhood externalities within or among various groups of residents as well as spatial factors like the individual choice of residential space and location it might be safely said that in the literature the only theoretical work which employs a long run dynamic approach to this kind of problem is a paper on dynamic models of segregation by thomas schelling 197 1 although his socioeconomic analysis has revealed some of the dynamic properties of a racially mixed area with neighborhood externalities his model itself is quite unsatisfactory from the economic point of view since it lacks individual utility functions and thereby disregards the aspect of the individual choice of space and location within the city 2 as a result he failed to analyze the effect of spatial segregation within the city on the long run nature of the residential composition of the city in this paper i develop a long run dynamic model of an open city which accommodates two groups of households for example blacks and whites rich and poor young and old with their utility functions depending on a consumption good and residential space i also assume two kinds of neighborhood externalities the first is called negative intergroup externalities that is the utility level of a typical household in one group is adversely affected by an increase in the number of households in the other group living in the city the second is called positive intragroup externalities that is the utility level of a typical household in one group is positively affected by an increase in the size of its own group in in the city first i define a mixed city equilibrium as a long run equilibrium which allows the two groups to coexist in the city in the long run and then introduce a dynamic adjustment process of household movement into and out of the city it is proved that the mixed city equilibrium is always unstable in the presence of negative intergroup externalities and or positive intragroup externalities if residential land is perfectly homogeneous and there is no differential transport cost incurred within the city it turns out however that in the case of a monocentric city with positive transport cost the mixed city equilibrium may be stable or unstable depending on the degree of neighborhood externalities because of the stabilizing effect of spatial segregation between the two groups within the city

how to grow a bubble a model of myopic adapting agents abstract we present a simple agent based model to study the development of a bubble and the consequential crash and investigate how their proximate triggering factor might relate to their fundamental mechanism and vice versa our agents invest according to their opinion on future price movements which is based on three sources of information i public information i e news ii information from their friendship network and iii private information our bounded rational agents continuously adapt their trading strategy to the current market regime by weighting each of these sources of information in their trading decision according to its recent predicting performance we find that bubbles originate from a random lucky streak of positive news which due to a feedback mechanism of these news on the agents strategies develop into a transient collective herding regime after this self amplified exuberance the price has reached an unsustainable high value being corrected by a crash which brings the price even below its fundamental value these ingredients provide a simple mechanism for the excess volatility documented in financial markets paradoxically it is the attempt for investors to adapt to the current market regime which leads to a dramatic amplification of the price volatility a positive feedback loop is created by the two dominating mechanisms adaptation and imitation which by reinforcing each other result in bubbles and crashes the model offers a simple reconciliation of the two opposite herding versus fundamental proposals for the origin of crashes within a single framework and justifies the existence of two populations in the distribution of returns exemplifying the concept that crashes are qualitatively different from the rest of the price moves

habits peers and happiness an evolutionary perspective the principal motivating factor in our lives is the pursuit of happiness in most cultures when seeking this end individuals place a high priority on income and spend much of their waking time procuring this intermediate goal the connection between income and happiness is by no means trivial however two critical factors come into play first beyond subsistence level the positive effect of a permanent change in income tends to be short lived we rapidly become accustomed to a more expensive lifestyle a common name for this feature is habit formation second the satisfaction derived from a given level of income is sharply dependent on how it compares to the income of peers see for example andrew b abel 1990 becker 1996 and william a brock and steven n durlauf 2001 for a demonstration of the influence of habits and peer comparisons over behavior and see shane frederick and george loewenstein 1999 for a review of the underlying psychology habits and peer comparisons mean that an individual is not concerned mainly with her absolute level of income but rather with the difference between her income and a benchmark that changes over time in recent years economists have become increasingly interested in this fact this interest has been both applied i e the study of habits and peer influences over behavior and the analysis of happiness surveys and theoretical i e a search for biological foundations but unlike other more developed areas of economics these two approaches remain fairly separate from each other in particular the existing theoretical work is motivated only by the most basic empirical observations and the existing applied work for the most part has not been influenced by theoretical results in this essay we seek to reduce the distance between these two literature strands in particuhabits peers and happiness an evolutionary perspective

financialization fundamentals and the time varying determinants of us natural gas prices abstract increasing empirical evidence shows that natural gas prices have decoupled from oil prices yet there remains an open question as to what are the determining factors of natural gas prices following the demise of oil indexation this paper aims to address this question using a dynamic model averaging dma approach dma can help identify key important price determinants and importantly does so within a time varying framework allowing us to document how the set of determinants has evolved in response to key market changes using time series data between 2001 and 2018 we demonstrate a clear declining role of oil prices in the natural gas pricing mechanism verifying the demise of indexation market or fundamental factors such as weather demand and supply conditions have at the same time become more important in addition our results illustrate an increasing role from financial markets captured by speculation related variables providing empirical evidence to support the recent literature on commodity market financialization the rising impact of speculation to natural gas prices introduces questions over how to balance market efficiency and risk management in the post indexation regime

total factor productivity growth technological progress and technical efficiency change dimensions of productivity change in yugoslavia 1965 1978 this article total factor productivity growth technological progress and technical efficiency change dimensions of productivity change in yugoslavia 1965 78 was reprinted with permission from the december 1982 issue of the economic journal this article proposes a methodology that decomposes total factor productivity change into two distinct elements technological progress and changes in technical efficiency technological progress is defined as the change in the best practice production frontier all other productivity change is attributed to technical efficiency change the article provides a theoretical framework for decomposing total factor productivity growth as well as a specification and estimation of the deterministic frontier production function it employs a programming technique to estimate a flexible functional form of the production frontier the paper then applies this technique to empirical data from yugoslavia of the period from 1965 to 1978 it concludes that for yugoslavia improvements to technical efficiency comprise the dominant contribution to total factor productivity change this agrees with accumulating evidence that in many developing economies productivity gain due to technological mastery of imported technology is substantial

re thinking the power transmission model for sub saharan africa abstract a vision for a united states of africa has been advocated since the dawn of independence by among others pioneers like kwame nkrumah gamal abdel nasser and julius nyerere more recently the idea gained new momentum through such initiatives as the new partnership for african development nepad and the african union au to create a single market of africa s 750 million people that is competitive within itself and within the global economy this would be achieved through a deliberate systematic and concerted effort to integrate upgrade and modernize infrastructure that would offer the required catalyst for economic growth however the prioritization by african policy makers of a grand plan to link up the entire african continent s electric power grid networks would appear to be incompatible with 21st century thinking the specifications for a centrally managed power grid were made by nicola tesla in 1883 and have served the power industry for over 125 years but are now obsolete in the era of digital micro electronics and smart grid concepts this paper examines some issues that surround the evolution of sub sahara african regional power pools and highlights the anomalies and perhaps wrong timing around the conceptualization and prioritization of grand inter state power grids the authors then propose an alternative model that conforms to a new and more sustainable paradigm in electricity supply economics the proposals are however not meant to provide a panacea but it is hoped that the article will ignite a debate that will lead to a lasting solution

a multi factor model with time varying and seasonal risk premiums for the natural gas market abstract in this paper we develop a quantitative model of the us natural gas market that explores its multi factor structure and its time varying and seasonal risk premiums with weekly spot and futures prices we show that three factors are preferred to describe the futures term structure and the time varying risk premiums are also significant moreover we found that the market implies a seasonal risk premium with two peaks and troughs in one year which is important to correctly price the futures by maturity month finally we link this seasonal risk premium to the uncertainty of the us natural gas demand and find a positive relationship between them these results reveal the complex aspect of the market and may have useful applications for other commodity sectors

how efficient are african electricity companies evidence from the southern african countries this paper is a first attempt at documenting efficiency levels in africa s electricity firms their evolution and the sources of this evolution the analysis is based on a sample of 12 operators providing services in the 12 country members of the southern africa power pool we focus on the changes in total factor productivity tfp of the largest operators in each country between 1998 and 2005 we then rely on a data envelopment analysis dea decomposition to identify the sources of the changes in tfp the results suggest fairly comparable levels of efficiency in the region and performance levels and evolution quite independent of the degree of vertical integration the presence of a private actor or the main sources of energy supply the analysis suggest that although the companies have not made significant improvements during the period of analysis in using their capital and human assets they have done much better in adopting better technologies and better commercial practices no clear correlation could be associated with the adoption of reforms during the last decade and data limitations impede a more refined assessment of the impact of reforms on efficiency at this stage

estimating the competitive storage model with trending commodity prices we present a method to estimate jointly the parameters of a standard commodity storage model and the parameters characterizing the trend in commodity prices this procedure allows the influence of a possible trend to be removed without restricting the model specification and allows model and trend selection based on statistical criteria the trend is modeled deterministically using linear or cubic spline functions of time the results show that storage models with trend are always preferred to models without trend they yield more plausible estimates of the structural parameters with storage costs and demand elasticities that are more consistent with the literature they imply occasional stockouts whereas without trend the estimated models predict no stockouts over the sample period for most commodities moreover accounting for a trend in the estimation imply price moments closer to those observed in commodity prices our results support the empirical relevance of the speculative storage model and show that storage model estimations should not neglect the possibility of long run price trends

the impact of the shale gas revolution on the u s and japanese natural gas markets we investigated whether the increase in the us shale gas production changed the structures of the us and japanese natural gas markets using market data for the period 2002 5 2012 5 our analysis consists of a structural break test and market integration analysis the bai and perron structural break test detected a break point of natural gas prices and consumption in 2005 as well as other external shocks hurricane katrina and the lehman shock that are irrelevant to shale gas development we eliminated the impact of these shocks by separating the data set using the breaks identified in our analysis we found the breaks skewed the estimation a market linkage existed between the us and japanese markets in the original data set while it did not in the separated data the vector autoregressive var model also indicated a significant change before and after the break point the us market had a one side influence on the japanese market before 2005 but the influence disappeared after 2005 our results implied that the shale gas revolution triggered by the increase in shale gas production in 2005 caused the change in the relationship between the us and japanese natural gas markets

equity and efficiency in human capital investment the local connection a general model of community formation and human capital accumulation with social spillovers and decentralized school funding is used to analyse the causes of economic segregation and its consequences for equity and efficiency significant polarization arises from minor differences in endowments preferences or access to capital markets this makes income inequality more persistent across generations but the same need not be true for wealth equilibrium stratification tends to be excessive resulting in low aggregate surplus whether state equalization of school resources can remedy these problems hinges on how purchased social and family inputs interact in education and in mobility decisions

heterogeneous effects of regulation on the efficiency of the electricity industry across european union countries abstract this paper focuses on the relationship between the stringency of regulation oecd indicators and total factor productivity tfp growth in the electricity sectors of 19 european union countries for the period 1994 2007 both the oecd regulatory indicator and the tfp growth index have been decomposed in order to bring to light a complex picture of interrelations in which the negative impact of the overall regulation on productivity is the result of opposite forces estimation results tell us that only the stringency of entry regulation significantly reduces technological change whereas vertical integration exhibits a negative and significant impact only on the catching up process pure efficiency change lastly we found an interesting result concerning the explanatory variables of the scale efficiency change in this case only public ownership matters in other terms high levels of public in the structure ownership of electric companies guarantee improvements in reaching the optimal scale of production these heterogeneous effects are also confirmed when we use a different measure of efficiency that is the distance of the actual from the optimal reserve margin

some evolutionary foundations for price level rigidity this paper shows that price rigidity evolves in an economy populated by imperfectly rational agents who experiment with alternative rules of thumb in the model firms must set their prices in face of aggregate demand shocks their payoff depends on the level of aggregate demand as well as on their own price and their neighbor s price the latter assumption captures local interactions despite the fact that the rational expectations equilibrium ree is characterized by a simple pricing rule that firms can easily adopt the economy does not converge to the ree for all parameter values when the volatility of monetary innovations is low and interactions among firms are high the aggregate price level exhibits rigidity in that it does not fully react to contemporaneous aggregate demand shocks we discuss the role of the nature of experimentation and of path dependence driven by interactions in explaining these results

does the volatility of commodity prices reflect macroeconomic uncertainty abstract while there exists numerous studies on the macroeconomic effects of oil and commodity shocks the literature is quite silent on the impact of macroeconomic uncertainty on oil and commodity prices and especially on their volatility this paper tackles this issue through the estimation of a structural threshold vector autoregressive tvar model on a sample of 19 commodity markets we aim at i assessing whether the effect of macroeconomic uncertainty shocks on commodity price returns depends on the degree of uncertainty and ii investigating the transfer from macroeconomic uncertainty to price uncertainty using a newly developed measure of commodity price uncertainty our findings show that both agricultural and industrial markets are highly sensitive to the variability and the level of macroeconomic uncertainty while the impact on precious metals is more parsimonious given their well identified safe haven role in time of economic turmoil in addition we find evidence that the recent 2007 09 recession has generated an unprecedented episode of high uncertainty in numerous commodity prices interestingly our analysis further reveals that volatility and uncertainty in prices can be disconnected this is especially true for the oil market as most important shocks in the 1990s and the beginning of the 2000s that lead to price volatility do not generate price uncertainty highlighting the relevance of our uncertainty measure in linking uncertainty to predictability rather than to volatility

a discrete choice model with social interactions with an application to high school teen behavior we develop an empirical discrete choice interaction model with a finite number of agents we characterize its equilibrium properties in particular the correspondence between interaction strength number of agents and the set of equilibria and propose to estimate the model by means of simulation methods in an empirical application we analyze the individual behavior of high school teenagers in almost 500 school classes from 70 schools in our baseline model endogenous social interaction effects are strong for behavior closely related to school truancy somewhat weaker for behavior partly related to school smoking cell phone ownership and moped ownership and absent for behavior far away from school asking parents permission for purchases intra gender interactions are generally much stronger than cross gender interactions in a model with school specific fixed effects social interaction effects are insignificant with the exception of intra gender interactions for truancy copyright c 2007 john wiley sons ltd

the social multiplier aggregate data is often used to make inferences about individual level behavior if there are social interactions in which one person s actions influence his neighbor s incentives or information then these inferences are inappropriate the presence of positive social interactions or strategic complementarities implies the existence of a social multiplier where aggregate relationships will overstate individual elasticities we present a brief model and then estimate the size of the social multiplier in three areas the impact of education on wages the impact of demographics on crime and group membership among dartmouth roommates in these contexts there is a significant social multiplier jel ho jo co

identification of endogenous social effects the reflection problem this paper examines the reflection problem that arises when a researcher observing the distribution of behaviour in a population tries to infer whether the average behaviour in some group influences the behaviour of the individuals that comprise the group it is found that inference is not possible unless the researcher has prior information specifying the compisition of reference groups if this information is available the prospects for inference depend critically on the population relationship between the variables defining reference groups and those directly affecting outcomes inference is difficult to implossible if these variables are functionally dependent or are statistically independent the prospects are better if the variables defining reference groups and those directly affecting outcomes are moderately related in the population

modeling choice interdependence in a social network this paper investigates how individuals product choices are influenced by the product choices of their connected others and how the influence mechanism may differ for fashion versus technology related products we conduct a novel field experiment to induce and observe choice interdependence in a closed social network in our experiment we conceptualize individuals choices to be driven by multiattribute utilities and we measure their initial attribute preferences prior to observing their choice interdependence and collecting network information these design elements help alleviate concerns in identifying social interaction effects from other confounds given that we have complete information on choices and their sequence we use a discrete time markov chain model nonetheless we also use a markov random field mrf model as an alternative when the information on choice sequence is missing we find significant social interaction effects our findings show that whereas experts exert asymmetrically gre

asymmetric reactions of the us natural gas market and economic activity this paper provides new empirical evidence on the asymmetric reactions of the us natural gas market and us economy to its market fundamental shocks we find that results based on a smooth transition vector autoregressive stvar model provides a plausible and robust explanation to the behavior of the us natural gas market which asymmetrically reacts in bad times and good times during times of recession natural gas production shrinks in response to a positive oil price shock while the corresponding response is found to be positive in times of expansion the positive relationship between the price of natural gas and crude oil is found to be more prominent in expansions especially in the long run in addition the results also reveal that us economic activity is much more sensitive to oil and natural gas price shocks occurring in bad times than in good times

further evidence on the debate of oil gas price decoupling a long memory approach abstract the long run oil gas price relationship has been challenged more often in recent years as these two prices have shown evidence of decoupling from each other this paper proposes the use of a long memory approach and a rolling windows method to model the time varying oil gas price relationship in three markets namely the united states europe and japan the results extend existing research conclusions on the oil gas price relationship and answer the question of whether it is a temporary phenomenon or a permanent market change our findings indicate that the us oil gas relationship remains nonstationary at almost all windows and illustrate strong evidence of decoupling conversely the european and asian oil gas prices exhibit temporary decoupling over time although the overall relationship still favours the oil indexation hypothesis the us experience suggests that oil and gas do not share the same fundamentals and a pricing hub can better reflect the true value of natural gas policy makers in europe and asia should reinforce their efforts towards a market based pricing mechanism for gas

cultural integration and its discontents a community s culture is defined by the preferences and equilibrium behaviours of its members contacts among communities alter individual cultures through two interrelated mechanisms behavioural adaptations driven by pay offs to coordination and preference changes shaped by socialization and self persuasion this paper explores the workings of these mechanisms through a model of cultural integration in which preferences and behaviours vary continuously it identifies a broad set of conditions under which cross cultural contacts promote cultural hybridization the analysis suggests that policies to support social integration serve to homogenize preferences across communities thereby undermining a key objective of multiculturalism yielding fresh insights into strategies pursued to influence cultural trends it also shows that communities benefit from having other communities adjust their behaviours

how does the u s natural gas market react to demand and supply shocks in the crude oil market abstract in this paper we use monthly data over the period from january 1976 to december 2012 and a structural var model to disentangle demand and supply shocks in the global crude oil market and investigate their effects on the real price of natural gas in the united states we identify the model by assuming that innovations to the real price of crude oil are predetermined with respect to the natural gas market and show that close to 45 of the variation in the real price of natural gas can be attributed to structural supply and demand shocks in the global crude oil market

productivity growth technical progress and efficiency change in industrialized countries this paper analyzes productivity growth in 17 oecd countries over the period 1979 1988 a nonparametric programming method activity analysis is used to compute malmquist productivity indexes these are decomposed into two component measures namely technical change and efficiency change we find that u s productivity growth is slightly higher than average all of which is due to technical change japan s productivity growth is the highest in the sample with almost half due to efficiency change jel c43 d24 in this paper we apply recently developed

performance based regulation of the electricity supply industry in hong kong an empirical efficiency analysis approach this paper presents an empirical efficiency analysis approach to analyze the efficiency and performance of utilities and its effects on prices under the price cap performance based regulation pbr model a data envelopment analysis dea like frontier based method is used to compute the total factor productivity with the malmquist productivity index results of case studies support the use of the approach to account for the relation of the x factor and the pbr model on the two power utilities in hong kong s electricity supply industry

rationalizability learning and equilibrium in games with strategic complementarities we study a rich class of noncooperative games that includes models of oligopoly competition macroeconomic coordination failures arms races bank runs technology adoption and diffusion r d competition pretrial bargaining coordination in teams and many others for all these games the sets of pure strategy nash equilibria correlated equilibria and rationalizable strategies have identical bounds also for a class of models of dynamic adaptive choice behavior that encompasses both best response dynamics and bayesian learning the players choices lie eventually within the same bounds these bounds are shown to vary monotonically with certain exogenous parameters we study the class of noncooperative supermodular games introduced by topkis 1979 and further analyzed by vives 1985 1989 who also pointed out the importance of these games in industrial economics supermodular games are games in which each player s strategy set is partially ordered the marginal returns to increasing one s strategy rise with increases in the competitors strategies so that the game exhibits strategic complementarity 2 and if a player s strategies are multidimensional marginal returns to any one com ponent of the player s strategy rise with increases in the other components this class turns out to encompass many of the most important economic applications of noncooperative game theory in macroeconomics diamond s 1982 search model and bryant s 1983 1984 rational expectations models can be represented as supermodular games in each of these models more activity by some members of the economy raises the returns to increased levels of activity by others in oligopoly theory some models of bertrand oligopoly with differentiated products qualify as supermodu lar games in these games when a firm s competitors raise their prices the marginal profitability of the firm s own price increase rises a similar structure is present in games of new technology adoption such as those of dybvig and spatt 1983 farrell and saloner 1986 and katz and shapiro 1986 when more users hook into a communication system or more manufacturers adopt an interface standard the marginal return to others of doing the same often rises similarly in some specifications of the bank runs model introduced by diamond and dybvig 1983 when more depositors withdraw their funds from a bank it is more worthwhile for other depositors to do the same in the warrant exercise

quantifying equilibrium network externalities in the ach banking industry we seek to estimate the causes and magnitudes of network externalities for the automated clearinghouse ach electronic payments system using a panel data set on individual bank usage of ach we construct an equilibrium model of consumer and bank adoption of ach in the presence of a network the model identifies network externalities from correlations of changes in usage levels for banks within a network from changes in usage following changes in market concentration or sizes of competitors and from adoption decisions of banks outside the network with small branches in the network and can separately identify consumer and bank network effects we structurally estimate the parameters of the model by matching equilibrium behavior to the data using simulated maximum likelihood and a data set of localized networks and use a bootstrap to recover confidence intervals the parameters are estimated with high precision and fit various moments of the data reasonably well we find that most of the impediment to ach adoption is due to large consumer fixed costs of adoption the deadweight loss from the network externality is moderate the optimal number of ach transactions is about 16 higher than the equilibrium level

the role of underground storage in the dynamics of the us natural gas market a threshold model analysis abstract natural gas is an important source of energy in the global economy hence understanding the drivers of its prices is of significant interest for the many economic agents this paper investigates the role of inventories for the dynamics of the u s natural gas market our contribution is twofold first within the threshold structural var framework we demonstrate that in a low inventory regime spot prices are more responsive to economic fundamentals in comparison to situation in which the inventories are high second we present evidence that the level of natural gas inventories have a significant effect on the relationship between spot and futures prices