the impact of fat tails on equilibrium rates of return and term premia abstract we investigate the impact of ignoring fat tails observed in the empirical distributions of macroeconomic time series on the equilibrium implications of the consumption based asset pricing model with habit formation fat tails in the empirical distributions of consumption growth rates are modeled as a dampened power law process that nevertheless guarantees finiteness of moments of all orders this renders model implied mean equilibrium rates of return and equity and term premia finite comparison with a benchmark gaussian process reveals that accounting for fat tails lowers the model implied mean risk free rate by 20 percent raises the mean equity premium by 80 percent and the term premium by 20 percent bringing the model implications closer to their empirically observed counterparts fat tails also increase the model implied volatility of the risk free rate and the equity premium

does the great recession imply the end of the great moderation international evidence in this paper we examine whether or not the great recession had a temporary or permanent effect on output growth volatility after years of low macroeconomic volatility since the early eighties based on break detection methods applied to a set of advanced countries our empirical results do not give evidence to the end of the great moderation period but rather that the great recession is characterized by a dramatic short lived effect on the output growth but not on its volatility we show that neglecting the breaks both in mean and in variance can have large effects on output volatility modeling based on garch specifications

censored latent effects autoregression with an application to us unemployment a new time series model is proposed to describe observed asymmetries in postwar unemployment data we assume that recession periods when unemployment increases rapidly are caused by unobserved positive shocks the generating mechanism of these latent shocks is a censored regression model where linear combinations of lagged explanatory variables lead to positive shocks while otherwise shocks are equal to zero we apply our censored latent effects autoregression clear to monthly us unemployment where the positive shocks are found to depend on lagged oil prices industrial production the term structure of interest rates and a stock market index the model fits the data well and its out of sample forecasts appear to outperform those from alternative models

testing for nonlinear dependence in daily foreign exchange rates the purpose of this article is to investigate whether daily changes in five major foreign exchange rates contain any nonlinearities although the data contain no linear correlation evidence indicates the presence of substantial nonlinearity in a multiplicative rather than additive form further examination reveals that a generalized autoregressive conditional heteroskedasticity model can explain a large part of the nonlinearities for all five exchange rates copyright 1989 by the university of chicago

evidence of nonlinearity in daily stock returns this article applies a newly developed statistical technique to time series of daily rates of return of 15 common stocks the technique involves estimating the bispectrum of the observed time series the bispectrum is defined as the double fourier transform of the third order cumulant function if the process generating rates of return is linear with independent innovations then the skewness of the bispectrum will be constant the article describes a test that can detect nonconstant skewness in the bispectrum hence if the test rejects constant skewness a nonlinear process is implied as a consequence the test can distinguish between white noise and purely random noise the results suggest that daily stock returns are generated by a nonlinear process

further evidence on the asymmetric behavior of economic time series over the business cycle evidence has recently been presented by salih neftci to support the hypothesis that recessions in economic activity tend to be steeper and more short lived than recoveries in economic activity that evidence however was confined to the behavior of the unemployment rate in the united states in this paper it is shown that when neftci s methods are applied to analyze the behavior of real gross national product investment and productivity in the united states or when they are used to analyze industrial production abroad the asymmetry hypothesis seems to be less compelling

outliers and garch models in financial data abstract we propose to extend the additive outlier ao identification procedure developed by franses and ghijsels franses p h ghijsels h 1999 additive outliers garch and forecasting volatility international journal of forecasting 15 1 9 to take into account the innovative outliers ios in a garch model we apply it to three daily stock market indexes and examine the effects of outliers on the diagnostics of normality

another look at swedish business cycles 1861 1988 this paper considers nine long swedish macroeconomic time series whose business cycle properties were discussed by englund persson and svensson 1992 using frequency domain techniques it is found by testing that all but two of the logarithmed and differenced series are nonlinear the observed nonlinearity is characterized by star models the statistical and dynamic properties of the estimated star models are investigated using among other things parametrically estimated local or sliced spectra cyclical variation at business cycle frequencies does not seem to be constant over time for all series and it is difficult to find a swedish business cycle only two series may be regarded as having genuinely asymmetric cyclical variation standard granger noncausality tests are adapted to the nonlinear star case and the null hypothesis of noncausality is tested for pairs of series the results point at strong temporal interactions between series they also indicate that the assumption of functional form linear or star strongly affects the outcome of these pairwise tests

distributional preferences and the incidence of costs and benefits in climate change policy we explore the relationship between willingness to pay wtp for climate change mitigation and distributional preferences by which we mean individuals opinions about who should be responsible for climate change prevention and whether the share of climate change impacts borne by the poor is a cause for concern we use 1 770 responses to an online stated preference survey the domestic costs in our survey s policy choice scenarios are expressed as a set of randomized shares across four different payment vehicles and the international cost shares are randomized across four groups of countries we also elicit respondents perceptions of the likely regressivity of climate change impacts under a policy of business as usual wtp is higher when larger cost shares are borne by parties deemed to bear a greater responsibility for mitigation and when respondents believe and care that the impacts of climate change may be borne disproportionately by the world s poor that wtp for an environmental policy depends on the distributional consequences of the policy is an unsettling result efficiency assessments are typically assumed to be separate from equity considerations in most benefit cost analyses

the impact of perception and other factors on the adoption of agricultural technology in the moret and jiru woreda district of ethiopia the objectives of this study are to examine both the significance of the impact of farmers perceptions regarding new technology for the adoption decision and how perceptions themselves are influenced by the decision to adopt new technology the study is based on data from 96 wheat farms in the moret and jiru woreda district of ethiopia the probit approach is used to analyse the adoption decision while the variables relevant to farmers perceptions are modelled using the ordered probit methodology a simultaneous equations model combining the probit and ordered probit approaches provides a useful approach to modelling the two way relationship between perception and adoption variables such as farm size farm income and soil type have a key role to play in the model perception is measured by eight different components and as there is a strong collinearity among these various measures a principal components analysis is attempted to draw the best possible linear combination of variables

unit roots and infrequent large shocks new international evidence on output abstract the nature and magnitude of the economic shocks that have affected the per capita gdp of 16 oecd countries are analyzed over a long period using the outlier method strong proof of infrequent large permanent and transitory shocks were found essentially resulting from the two major wars in the twentieth century the recession in the 1920s the great depression among others we also examine the nature of the output trend by combining different tests of non stationarity on different gdp series corrected by the outliers detected it is shown that the per capita gdp series cannot reject the unit root hypothesis in 13 of the 16 countries examined no conclusion could be drawn for the other countries because the test results were contradictory

modeling structural breaks in economic relationships using large shocks abstract this paper introduces a new model of structural breaks in the coefficients of economic relationships which allows them to be driven by large past economic shocks the breaks generated by these shocks can be taken to reflect stochastic changes in agents decisions or beliefs triggered by extraordinary economic events our model specifies that both the timing and size of breaks are stochastic the last property of it enables us to investigate qualitative effects that large shocks can have on economic relationships as an empirical application of our model the paper investigates the stability the oil economy relationship since the early sixties from the six large oil shocks identified by our data the paper shows that only the first oil shock at the end of 1973 has caused a major long term adverse effect on economic activity all the large oil price shocks that have happened since then did not have any significant negative effects on the slope of the oil economy relationship

how resilient is la reunion in terms of international tourism attractiveness an assessment from unit root tests with structural breaks from 1981 2015 even if local policymakers increasingly claim that tourism is one of the key factors of future economic development for the french small island la reunion international tourist arrivals are observed to be locked in a stagnation phase since the beginning of the 2000s starting from this stylised fact this article aims to study if this phenomenon results from major external events hurting this economy regularly next by using univariate unit root procedures with structural breaks we test for evidence of permanent or transitory effects of external shocks on international tourist inflows total by source markets and by category over the period 1981 2015 finally the empirical analysis allow us to reject the null of a unit root then stagnation of tourism arrivals to la reunion is not due to exogenous shocks but probably results from endogenous impediments within the domestic tourism industry and unsuitable public policies

a class of nonlinear arch models a class of nonlinear arch models is suggested the proposed class encompasses several functional forms for arch which have been put forth in the literature a lagrange multiplier test is developed to test engle s arch specification against the wider class of models this test provides an easily computed diagnostic check of the adequacy of an arch model after it has been estimated the theory is applied to a number of weekly exchange rate series and we find strong evidence of nonlinear arch

whether crop diversification is a desired strategy for agricultural growth in bangladesh abstract this study aimed at examining the merit of crop diversification as a strategy for agricultural growth in bangladesh specifically the existence of economies of diversification scale economies and diversification efficiencies at the farm level were examined using a stochastic input distance function approach the results reveal strong evidence of diversification economies amongst most crop enterprises except the combination of modern rice and modern wheat enterprises ray economies of scale exist in bangladeshi cropping system also significant are efficiency gains made from diversification among cropping enterprises the key policy implication is that crop diversification should be a desired strategy for agricultural growth in bangladesh development of the rural infrastructure is also essential as this will not only improve technical efficiency but may also synergistically promote crop diversification by opening up opportunities for technology diffusion marketing storage and resource supplies

segmented trends and non stationary time series since the influential work of charles r nelson and charles plosser 1982 many empirical studies have concluded that macroeconomic time series are difference stationary this paper proposes the segmented trend model as an alternative in which the series is the sum of a nonstationary trend and a stationary cycle and where the trend shows infrequent shifts the paper proposes tests between the difference stationary and segmented trends models and applies these to the data of nelson and plosser in general the results indicate that prices are difference stationary but quantities follow segmented trend processes copyright 1989 by royal economic society

cutting the gordian knot in climate change policy ongoing conflict over the fair allocation of greenhouse gas emissions among nations is a significant impediment to progress in international climate change negotiations this article considers the strengths and weaknesses of a crucial argument within the allocation debate asserting the atmospheric capacity to absorb greenhouse gases should be distributed on an equal per capita basis while noting the argument s many appealing qualities the paper argues that the per capita perspective also encompasses important practical and ethical limitations besides potentially encouraging population growth and discriminating against those with greater but still legitimate energy needs early evidence suggests that the equal per capita idea may hinder progress in climate change talks by invoking a more absolutist and uncompromising rhetoric of rights alternative ideas of fairness such as the distinction between subsistence and luxury emissions or the common heritage of mankind idea offer a more flexible mix of egalitarian and other allocation principles that should be considered carefully even by those sympathetic to the equal per capita perspective

bounded influence estimator for garch models evidence from foreign exchange rates previous research indicates that the maximum likelihood estimates of generalized autoregressive conditional heteroscedasticity garch models on foreign exchange rates under various distributional assumptions are sensitive to the presence of outliers the advantage of the proposed bounded influence estimator bie is that it limits the influence of a small subset of data and is asymptotically normal the bie provides more consistent and robust estimates than maximum likelihood estimator mle and semi parametric estimator both of which tend to underestimate volatility persistence due to outliers it is thus robust to outliers and model misspecification results of bie estimates of garch models on the exchange rate series of five major currencies indicate that bie offers an efficient mechanism for down weighting outlying observations and is a competitive alternative to mle

farm household efficiency in bangladesh a comparison of stochastic frontier and dea methods this study compares estimates of technical efficiency obtained from the stochastic frontier approach and the data envelopment analysis dea approach using farm level survey data for rice farmers in bangladesh technical inefficiency effects are modelled as a function of farm specific socioeconomic factors environmental factors and irrigation infrastructure the results from both the approaches indicate that efficiency is significantly influenced by the factors measuring environmental degradation and irrigation infrastructure

nonlinear dynamics and stock returns simple deterministic systems are capable of generating chaotic output that mimics the output of stochastic systems for this reason algorithms have been developed to distinguish between these two alternatives these algorithms and related statistical tests are also useful in detecting the presence of nonlinear dependence in time series in this article the authors apply these procedures to stock returns and find evidence that indicates the presence of nonlinear dependence on weekly returns from the center for research in security prices value weighted index copyright 1989 by the university of chicago

is the business cycle characterized by deterministic chaos abstract tests are conducted on u s macroeconomic data for the presence of low dimensional deterministic chaos where deterministic chaos is defined as in grandmont s 1985 walras bowley lecture or in brock 1986 the idea is to test for evidence of endogenous instability causing the business cycle low order autoregressions are hard to reject with our methods evidence of chaos is weak but our tests may be too weak to detect it evidence of nonlinearity is present in employment 1950 i to 1983 iv unemployment 1949 i to 1982 iv monthly post war industrial production and pig iron production 1877 1937

exploring long run relationship and error correction of thai output and price as the thai economy has integrated into the world system it increasingly endures not only internal circumstances but also external turmoils stabilizing the country s growth and inflation from macroeconomic shocks has then become a challenge to policymakers this study thus concentrates on investigating the long run relationship and the adjustment process towards the equilibrium of output and price of thailand from 2001 to 2014 for this purpose the dynamic relationship cointegration property and error correction term are explored by dols various cointegration tests and ecm the cointegration test also remarks the possibility of monetary policymakers to surprise the market in order to expect the increase in output it also reconfirms that the interest rate tends to be a passive monetary instrument in curbing inflationary moreover the adjustment process to the long run of both output and price is found to have a symmetric cointegration property which implies the systematic ecm the symmetric error correction test presents the significantly negative elimination in the next quarter towards long term equilibrium the monetary policymakers thus seem to react to the rise in inflation uncertainty by keeping down inflation meanwhile the output level tends to have faster adjustment speed than that of the price level

are business cycles asymmetric a correction neftci 1984 proposed a nonparametric test procedure for determining whether business cycles are asymmetric in the sense that contractions are steeper than expansions he found evidence of this type of asymmetry in postwar quarterly u s unemployment variables this comment identifies a probable error in neftci s empirical work that reverses the significance of his results for the unemployment rate and it suggests that this test may have low power and be sensitive to measurement error

did the green revolution concentrate incomes a quantitative study of research reports abstract a review of more than 300 studies on the green revolution published during 1970 1989 shows that about 80 of those studies which had conclusions on the distributional effects of the new technology found that inequality increased both interfarm and interregional this evidence diverges from the position of action agencies which support and participate in this technological strategy toward agricultural and rural development an evaluation of the studies using their results as data for a statistical analysis reveals that the authors conclusions on the question of whether income concentration increased depended on such structural and methodological characteristics as the regional origin of authors location of the study area methodology followed and the geographic extension of the study area for example studies done by western developed country authors those employing an essay approach and those looking at a multicountry region are most likely to conclude that income inequalities increased by contrast work done by asian origin authors with study areas located in india or the philippines and using the case method are more likely to conclude that increasing inequality is not associated with the new technology

international equity and differentiation in global warming policy ne of the major obstacles to reaching a comprehensive agreement on global warming is the setting of greenhouse gas emission reduction targets for individual countries long standing tensions between industrialized and developing countries have raised the issue of equity in burden sharing moreover individual industrialized nations have pleaded special circumstances and have sought differentiation in their obligations this paper analyzes alternative rules for distributing tradable carbon dioxide emissions permits a non linear programming model which distinguishes between allocation based and outcome based rules is used to analyze the relative welfare outcomes the model is applied to the world body of nations and yields several important policy implications

estimating farm level input demand and wheat supply in the indian punjab using a translog profit function application of the translog profit function to farm level data from punjab india allowed a more disaggregated analysis of the farm production structure compared to the case of cobb douglas formulation the flexibility afforded by translog formulation permitted measurement of the different impacts that exogenous variables have within and across input demand and output supply functions policy relevant elasticity estimates with respect to variable inputs and output prices fixed inputs a few soil related state of nature variables measured by soil analysis and education which are usually considered constraints to farm production were obtained and two examples of policy applications were developed

large shocks small shocks and economic fluctuations outliers in macroeconomic time series summary we analyse fifteen post world war i1 us macroeconomic time series using a modified outlier identification procedure based on tsay 1988a large shocks appear to be present in all the series we examined furthermore there are three basic outlier patterns i outliers seem to be associated with business cycles 2 outliers are clustered together both over time and across series 3 there appears to be a dichotomy between outlier behaviour of real versus nominal series also after controlling for outliers much of the evidence of non linearity in many of the time series is eliminated

are economic time series asymmetric over the business cycle it has long been argued that major cyclical variables such as the unemployment rate display an asymmetric behavior over various phases of the business cycle the paper provides a statistical test for this hypothesis using the framework of finite state markov processes i implement a test to see if the behavior of the unemployment rate is characterized by sudden jumps and slower drops it is argued that the framework provided in the paper can also be used to test other sample path properties of economic time series

characterizing nonlinearities in business cycles using smooth transition autoregressive models during the past few years investigators have found evidence indicating that various time series representing business cycles such as production and unemployment may be nonlinear in this paper it is assumed that if the time series is nonlinear then it can be adequately described by a smooth transition autoregressive star model the paper describes the application of these models to quarterly logarithmic production indices for 13 countries and europe tests reject linearity for most of these series and estimated star models indicate that the nonlinearity is needed mainly to describe the responses of production to large negative shocks such as oil price shocks

zimbabwe s maize based green revolution preconditions for replication abstract the green revolution was launched in 1960 in zimbabwe five years before it got underway in india since zimbabwe s green revolution was spearheaded by white commercial farmers however it was ignored by africa s new leaders in the 1960s as they experimented with state farms from moscow communal farms from china and land settlement schemes from israel at zimbabwe s independence in 1980 the new majority ruled government introduced a number of programs to help smallholders increase food and cash crop production drawing on a backlog of hybrid maize varieties expanded access to credit higher guaranteed government maize prices and marketing subsidies smallholders doubled maize production during 1980 1986 zimbabwe s maize based green revolution challenges those who allege that hybrid maize cannot compete with sorghum in low rainfall areas and that it is unsuitable for resource poor farmers because of the need to purchase new seed each year today virtually 100 of zimbabwe s maize area is under hybrids and short season hybrids are outcompeting other foodgrains in many low rainfall areas zimbabwe s biggest challenge is to develop cost effective marketing policies and institutions to sustain its maize based green revolution countries trying to replicate zimbabwe s success story should focus on fulfilling four interrelated preconditions political technological economic and institutional

shifting trends segmented trends and infrequent permanent shocks abstract a stochastic trend model is considered in which permanent shocks occur infrequently and randomly we show that this model is observationally equivalent to shifting segmented deterministic trend models moreover we show that standard full sample time series methods are incapable of distinguishing between small frequent permanent shocks and large infrequent permanent shocks an outlier search however reveals substantial evidence of large infrequent shocks to the gnp deflator and that these shocks account for most of the persistence in the gnp deflator for real gnp evidence of infrequent permanent shocks is weaker

output growth and its volatility the gold standard through the great moderation this study examines the relationship between u s output growth and its volatility over the period 1876 i to 2012 ii we adjust the data for outliers and structural breaks we employ generalized autoregressive conditional heteroskedasticity garch and exponential garch egarch specifications normality and homoskedasticity appear only in the garch or egarch model that corrects for the outliers when including the break in the mean equation high volatility persistence remains after also accommodating the breaks in the variance equation the integrated garch effect proves spurious either for the symmetric or the asymmetric model finally our empirical results suggest that the finding of higher output growth volatility stimulating output growth and higher output growth reducing its volatility obtained from the symmetric garch in mean garch m model also proves spurious as a result of the emergence of an asymmetric effect our more appropriately specified asymmetric egarch m model suggests positive volatility in mean and level effects in the long period real gross national product series

do fluctuations in u s inflation rates reflect infrequent large shocks or frequent small shocks we investigate whether fluctuations in u s inflation rates are better described by infrequently occurring large shocks or by frequently occurring small shocks we estimate a model that encompasses the two hypotheses within the framework of non gaussian state space models our results indicate support for infrequently occurring large shocks but this weakens somewhat once we allow for outliers and conditional heteroskedasticity it appears that for the purpose of forecasting monthly u s inflation rates recognizing the distinction between frequent small shocks and infrequent large shocks does not matter much once outliers and conditional heteroskedasticity are allowed for

asymmetric fluctuations in consumption abstract this paper develops simple models of consumption which allow for the possibility that decreases in consumption are less frequent but more severe than increases statistical tests provide some support for this asymmetry

a fallacy of composition the representative agent framework has endowed macroeconomists with powerful microeconomic tools unfortunately it has also blurred the distinction between statements that are valid at the individual level and those that apply to the aggregate in this paper the author argues that probability theory puts strong restrictions on the joint behavior of a large number of units that are less than fully synchronized many fallacies arise from disregarding these restrictions for example asymmetric factor adjustment costs at the firm level need not imply asymmetric responses of aggregate employment flows to positive and negative shocks copyright 1992 by american economic association

technical efficiency of alternative farming systems the case of greek organic and conventional olive growing farms abstract olive growing is a major farming activity in greek agriculture this paper analyzes empirically the technical efficiency of organic and conventional olive growing farms using a stochastic production frontier methodology and a translog functional specification findings indicate that the organic olive growing farms examined exhibit a higher degree of technical efficiency relative to their production frontier than do conventional olive growing farms reasons may include lower profit margins and restrictions on inputs permitted thus forcing organic farmers to be more cautious with input use however both input and output oriented technical efficiency scores are still relatively low for both types of olive farming thus there is considerable scope for cost reducing and farm income improvement in both farming modes this could prove crucial for the long run viability and the future course of the sector

role of agricultural research in poverty reduction lessons from the asian experience abstract the poor spend much of their income on food depend primarily on labour earnings and tend to reside in marginal agricultural areas to reduce poverty agricultural research should aim to ensure adequate food supplies by developing yield increasing technologies to increase labour demand by developing labour using technologies and to develop technologies suitable for marginal areas this article seeks to identify appropriate technologies that agricultural research should generate for poverty reduction the identification is based on a review of the experience of the green revolution in rice production in asia and an assessment of the changing structure of income sources among rural households in the philippines

pesticides productivity and farmer health a philippine case study health is recognized as one of the most important components of the human capital of rural people in developing countries there is a growing body of literature showing the productivity effects of health associated with nutrition e g bliss and stern 1978 strauss 1986 deolalikar 1988 pitt rosenzweig and hassan 1990 in this literature the productivity effects of health are inferred either by correlating health indicators with wages or by including health indicators in an agricultural production function the human capital literature also has demonstrated that farmer education plays an important role in the allocative and technical efficiency of farmers welch 1970 schultz 1975

factors influencing adoption of land enhancing technology in the sahel lessons from a case study in niger abstract technical change through the introduction of land enhancing conservation technologies is essential to economic growth in the sahel tobit analysis was used to identify factors that motivate level and intensity of adoption of specific soil and water management technologies the results show that higher percentage of degraded farmland extension education lower risk aversion and the availability of short term profits are important for increasing the adoption and intensity of use of improved tassa and half crescent shaped earthen mounds age and attitudes to differential gains between farm and non farm income showed no influence on adoption three main policy implications emerge from these findings first technologies should be targeted to locations that have large percentages of degraded farmlands the probability of adoption and intensity of use are likely to be high at such locations second there is the need to provide extension education that demonstrates risk reduction capacities of conservation techniques this will make available information capable of stimulating adoption of land enhancing technologies finally policy makers should not seek to target innovations to younger farmers because age has no relationship to adoption of the improved tassa and half crescent shaped earthen mounds lessons from the case study have broad relevance to cropped areas in the sahel

volatility persistence in crude oil markets financial market participants and policy makers can benefit from a better understanding of how shocks can affect volatility over time this study assesses the impact of structural changes and outliers on volatility persistence of three crude oil markets brent west texas intermediate wti and organization of petroleum exporting countries opec between january 2 1985 and june 17 2011 we identify outliers using a new semi parametric test based on conditional heteroscedasticity models these large shocks can be associated with particular event patterns such as the invasion of kuwait by iraq the operation desert storm the operation desert fox and the global financial crisis as well as opec announcements on production reduction or us announcements on crude inventories we show that outliers can bias i the estimates of the parameters of the equation governing volatility dynamics ii the regularity and non negativity conditions of garch type models garch igarch figarch and hygarch and iii the detection of structural breaks in volatility and thus the estimation of the persistence of the volatility therefore taking into account the outliers on the volatility modelling process may improve the understanding of volatility in crude oil markets

further investigation of the uncertain trend in us gdp the presence of deterministic or stochastic trend in us gdp has been a continuing debate in the literature of macroeconomics ben david and papell 1995 found evidence in favour of trend stationarity using the secular sample of maddison 1991 more recently murray and nelson 2000 correctly criticized this finding arguing that the maddision data are plagued with additive outliers ao which bias inference towards stationarity hence they propose to set the secular sample aside and conduct inference using a more homogeneous but shorter time span post wwii sample in this article we re visit the maddison data by employing a test that is robust against ao s our results suggest the us gdp can be modelled as trend stationary process

nonlinear business cycle dynamics cross country evidence on the persistence of aggregate shocks i introduction economists have long been interested in the dynamics of business cycles particularly regarding the symmetry of expansions and contractions more recently the specification of stochastic trends in economic growth has generated concerns about the relative persistence of positive and negative shocks to the economy several papers have looked at the persistence of business cycles including nelson and plosser 1982 campbell and mankiw 1987 cochrane 1988 diebold and rudebusch 1989 balke and fomby 1990 zelhorst and de haan 1994 and bradley and jansen 1995 while results vary especially on the issue of a unit root in output the overarching result is that output fluctuations are highly persistent one question not asked by the above authors is whether business cycle dynamics are asymmetric this issue has been investigated by neftci 1984 falk 1986 delong and summers 1986 hamilton 1989 diebold and rudebusch 1990 and terasvirta and anderson 1991 these authors take a variety of approaches but they reach a general conclusion that there is some evidence of asymmetric business cycle dynamics however most of these studies ask if contractions are shorter and steeper than expansions except hamilton 1989 they do not ask if there is a difference in persistence due to the asymmetries in a recent paper beaudry and koop 1993 propose a set of methods for simultaneously examining these two questions specifically beaudry and koop bk recommend the augmentation of the standard arma representation of real output growth through the inclusion of a nonlinear term that captures the relative state of the economy this augmentation provides for nonlinear dynamics and the possibility of asymmetric dynamic responses to positive and negative shocks in addition calculation of the implied impulse responses permits detection of the relative persistence implied by the combination of asymmetric cycle dynamics and stochastic trend based upon their analysis of u s data bk conclude that the response of the economy to positive and negative shocks is indeed asymmetric and the imposition of symmetry on impulse responses has likely led to misleading measures of persistence bk p 162 as a result bk conclude we find that the effects of negative shocks to be mainly temporary and the effects of positive shocks to be very persistent bk p 162 if bk s results are correct they have strong implications for the way macro economists view economic fluctuations and will in their words contribute to a reappraisal of some macroeconomic theories that is bk s results suggest that macroeconomic models must be revised to provide for temporary effects of negative shocks but permanent effects of positive shocks because of the potential importance of bk s results we examine the robustness of those results by modifying and extending bk s proposed methods of testing not only do we extend the analysis to the other six g7 countries besides the united states but also we redefine in a sensible way the nature of the nonlinear dynamics overall our results from other economies provide only mixed support for the asymmetry of cyclical dynamics and the lack of persistence of negative shocks ii the model to be estimated in the bk framework the estimated model includes an asymmetric response term the asymmetry is generated by a variable that measures the strength of a recession the variable is calculated as the distance between current real gdp and the previous peak level of real gdp that is bk define a measure they call current depth of the recession cdr where 1 cdr sub t max y sub t j sub j greater than or equal to 0 y sub t with this definition in place bk recommend augmenting an autoregressive model of real gdp growth as 2 phi l delta y sub t delta omega l 1 cdr sub

environmental impacts of technological change in bangladesh agriculture farmers perceptions determinants and effects on resource allocation decisions this article measures the impact of modern technology adoption in raising farmers environmental awareness and the impact of farmers environmental awareness on resource use by utilizing survey data from 21 villages in three agro ecological regions of bangladesh the econometric analysis is based on the application of the tobit model explaining farmers environmental awareness in the first stage and a profit function examining environmental awareness and resource use relationships in the second stage results reveal that the level and duration of involvement with modern technology raises farmers environmental awareness and that farmers environmental awareness reduces resource use including chemicals farmers who are aware of the adverse environmental impacts of modern agricultural technology use lower amounts of all inputs in order to avoid further environmental damage therefore efforts to raise farmers environmental awareness are expected to enhance intangible benefits accruing from a relatively less chemical intensive environment

testing for arch in the presence of additive outliers in this paper we investigate the properties of the lagrange multiplier lm test for autoregressive conditional heteroskedasticity arch and generalized arch garch in the presence of additive outliers ao s we show analytically that both the asymptotic size and power are adversely affected if ao s are neglected the test rejects the null hypothesis of homoskedasticity too often when it is in fact true while the test has difficulty detecting genuine garch effects several monte carlo experiments show that these phenomena occur in small samples as well we design and implement a robust test which has better size and power properties than the conventional test in the presence of ao s applications to the french industrial production series and weekly returns of the spanish peseta us dollar exchange rate reveal that sometimes apparent garch effects may be due to only a small number of outliers and conversely that genuine garch effects can be masked by outliers

large shocks in the volatility of the dow jones industrial average index 1928 2013 we determine the events that cause large shocks in volatility of the djia index over the period 1928 2013 using a new semi parametric test based on conditional heteroscedasticity models we find that these large shocks can be associated with particular events financial crashes elections wars monetary policies etc we show that some shocks are not identified as extraordinary movements by the investors due to their occurring during high volatility episodes especially the 1929 1934 1937 1938 and 2007 2011 periods