did the elimination of mandatory retirement affect faculty retirement a special exemption from the 1986 age discrimination act allowed colleges and universities to enforce mandatory retirement of faculty at age 70 until 1994 we construct a survey that permits us to compare faculty turnover rates before and after the law changed at a large sample of institutions with defined contribution pension plans after the elimination of compulsory retirement the retirement rates of 70 and 71 year olds fell by two thirds and were comparable to rates of 69 year olds these findings indicate that u s colleges and universities will experience a rise in the number of older faculty over the coming years jel j26 i21

modeling the co movements between crude oil and refined petroleum markets abstract in this paper we investigate two types of asymmetries i e the asymmetry in the lower and upper tail dependences and the asymmetry in the propagation of crisis bubble between crude oil market and refined petroleum markets based on copula models thirteen copula models with different types of dependence structures and time varying dependence parameters are considered we find that in general the malm copula fits our sample data best based on aic criterion we find that lower and upper tail dependences are both positive indicating that crude oil and refined product markets tend to move together using the asymmetric copulas we find asymmetry in tail dependence between crude oil and heating oil returns and that between crude oil and jet fuel returns interestingly upper tail dependence is significantly greater than the lower tail dependence for the pre crisis period while the result is reversed for the post crisis period finally although our data prefers the nonexchangeable malm copula the asymmetry in the propagation of crisis bubble between crude oil and refined product returns is very weak

the effect of pension plan type on retirement age distinguishing plan incentives from career length preferences the widespread movement from dened benet db plans to dened contribution dc plans over the past few decades has transferred much of the retirement savings risk from the institution to the individual particularly in the private sector this study uses the retirement condence

pension plan characteristics and framing effects in employee savings behavior abstract defined contribution pensions in many postsecondary institutions are funded by a combination of an employer premium and a mandatory employee premium individuals can also contribute to a supplemental savings account holding constant total compensation standard reasoning suggests that supplemental savings should depend negatively on the sum of the employer and employee pension contributions contrarily we find that the supplementary savings of professors are significantly more sensitive to employee contributions than to employer contributions this asymmetry is consistent with different marginal propensities to save out of the salary and pension components of compensation nevertheless impacts on lifetime utility are relatively modest

income and price elasticities of energy consumption in egypt a time series analysis abstract the purpose of this paper is to provide empirical estimates of the price and income elasticities of energy consumption in egypt it fills an important gap since policy discussion of energy pricing issues has so far been based more on assumptions than on hard evidence the paper shows that the real relative price of energy has been falling steadily since 1972 while per capita energy consumption rose some 50 over the decade 1972 81 evidence produced in this exercise indicates quite clearly that price and income elasticities of energy consumption are significantly much lower than was generally believed

should investors include commodities in their portfolios after all new evidence abstract this paper investigates whether an investor is made better off by including commodities in a portfolio that consists of traditional asset classes first we revisit the posed question within an in sample setting by employing mean variance and non mean variance spanning tests then we form optimal portfolios by taking into account the higher order moments of the portfolio returns distribution and evaluate their out of sample performance under the in sample setting we find that commodities are beneficial only to non mean variance investors however these benefits are not preserved out of sample our findings challenge the alleged diversification benefits of commodities and are robust across a number of performance evaluation measures utility functions and datasets the results hold even when transaction costs are considered and across various sub periods not surprisingly the only exception appears over the 2005 2008 unprecedented commodity boom period

an adaptive wavelet neural network based energy price forecasting in electricity markets in a competitive electricity market an accurate forecasting of energy prices is an important activity for all the market participants either for developing bidding strategies or for making investment decisions an adaptive wavelet neural network awnn is proposed in this paper for short term price forecasting stpf in the electricity markets a commonly used mexican hat wavelet has been chosen as the activation function for hidden layer neurons of feed forward neural network ffnn to demonstrate the effectiveness of the proposed approach day ahead prediction of market clearing price mcp of spain market which is a duopoly market with a dominant player and locational marginal price lmp forecasting in pjm electricity market are considered the forecasted results clearly show that awnn has good prediction properties compared to other forecasting techniques such as wavelet arima multi layer perceptron mlp and radial basis function rbf neural networks as well as recently proposed fuzzy neural network fnn

a note on the conditional correlation between energy prices evidence from future markets abstract we model the joint movements of daily returns on one month futures for crude oil heating oil and natural gas through the multivariate garch with dynamic conditional correlations and elliptical distributions introduced by pelagatti and rondena pelagatti m m rondena s 2007 dynamic conditional correlation with elliptical distributions unpublished manuscript universita di milano bicocca august futures prices of crude and heating oil covary strongly the conditional correlation between the futures prices of natural gas and crude oil has been rising over the last 5 years however this correlation has been low on average over two thirds of the sample suggesting that future markets have no established tradition of pricing natural gas as a function of developments on oil markets

does outlawing mandatory retirement reduce public pension benefit claim exploiting the 2011 abolishment of the mandatory retirement provision that had allowed employers to force retirement of their 65 or older employees in the uk this paper estimates the effect of out

prospects in the academic labor market for economists this paper discussed what the academic labor market for economists is likely to look like in the years ahead after tracing out trends in phd production of new economists including the increasing share of new phds who are foreign residents it presents new evidence on the growing use of part time and full time non tenure track faculty in u s economics departments the growing salary differentials between economists employed at private and public doctoral universities and how economists salaries have changed relative to those of faculty in other disciplines

retirement in the uk in common with other oecd countries the uk experienced more than two decades of declining labour market activity among older men from the 1970s to the early 1990s a trend that has only recently shown signs of being reversed retirement decisions are heavily shaped by institutional context and in the uk this has led to there being two distinct groups with very different retirement experiences at the top of the wealth distribution early retirement has typically been influenced by private occupational pensions at the bottom of the wealth distribution individuals are even more likely to be not working in their 50s but do not typically define themselves as retired and draw on income support or more usually disability benefits policy makers keen to increase effective retirement ages will need to consider the very different circumstances of these two groups

short term load forecasting methods an evaluation based on european data this paper uses intraday electricity demand data from ten european countries as the basis of an empirical comparison of univariate methods for prediction up to a day ahead a notable feature of the time series is the presence of both an in traweek and an intraday seasonal cycle the forecasting methods considered in the study include arima modeling periodic ar modeling an extension for double seasonality of holt winters exponential smoothing a recently proposed alternative exponential smoothing formulation and a method based on the principal component analysis pca of the daily demand profiles our results show a similar ranking of methods across the 10 load series the results were disappointing for the new alternative exponential smoothing method and for the periodic ar model the arima and pca methods performed well but the method that consistently performed the best was the double seasonal holt winters exponential smoothing method

dynamics of oil price precious metal prices and exchange rate this study examines the co movements and information transmission among the spot prices of four precious metals gold silver platinum and palladium oil price and the us dollar euro exchange rate we find evidence of a weak long run equilibrium relationship but strong feedbacks in the short run the spot precious metal markets respond significantly but temporarily to a shock in any of the prices of the other metal prices and the exchange rate furthermore we discover some evidence of market overreactions in the palladium and platinum cases as well as in the exchange rate market in conclusion whether there are overreactions and re adjustments or not investors may diversify at least a portion of the risk away by investing in precious metals oil and the euro policy implications are provided

dependence and extreme dependence of crude oil and natural gas prices with applications to risk management abstract in this article we show how the copula garch approach can be appropriately used to investigate the conditional dependence structure between the crude oil and natural gas markets as well as to derive implications for portfolio risk management in extreme economic conditions using daily price data from january 1997 to october 2011 our in sample results show evidence of asymmetric dependence between the two markets the crude oil and gas markets tend to comove closely together during bullish periods but not at all during bearish periods moreover taking the extreme comovement into account leads to an improvement in the accuracy of the out of sample value at risk forecasts

mandatory retirement and older worker employment in this paper we take advantage of differences in the legal status of mandatory retirement in canada across jurisdictions and over time to assess its impact on the share of older people working the results suggest that making mandatory retirement illegal would have little effect on the size of the older workforce and therefore such a policy alone would do little to alleviate problems associated with an aging population and the consequent decline in the share of the population employed jel classification j26 j88 retraite obligatoire et emploi des travailleurs plus ges ce memoire tire profit du fait que les regles de la retraite obligatoire ont varie au canada dans le temps et d une juridiction a l autre pour etudier l impact de ces regles sur la proportion des personnes plus gees qui travaillent les resultats suggerent que rendre la retraite obligatoire illegale aurait peu d effet sur la taille de main d uvre plus gee et donc qu une telle politique en soi ferait peu pour attenuer les problemes associes au vieillissement de la population et au declin qui s ensuit dans la proportion de cette population au travail

how do journal quality co authorship and author order affect agricultural economists salaries utilizing an original data set containing annual salaries and peer reviewed publication histories for 326 faculty members from top ranked ph d granting programs we examine the labor market for academic agricultural economists the results suggest that higher quality publications have a greater impact on annual earnings that sole authored articles have a higher return than multi authored articles and that no wage premium exists for being the lead author of a non alphabetic article

the short and long run efficiency of energy precious metals and base metals markets evidence from the exponential smooth transition autoregressive models abstract the aim of this paper is to investigate the long and short run relationship between spot and futures prices of the energy precious metals and base metals markets we analyze daily data from january 1985 to february 2019 the empirical findings based on the cointegration test which follows a nonlinear process suggest that the spot prices of energy and metals assets have long run relationships with their futures prices nonparametric granger causality test results also indicate bi directional causality among futures and spot prices these findings indicate that the energy and metals markets are informationally efficient in the sense of fama 1970

on the short and long run efficiency of energy and precious metal markets this article contributes to the related literature by empirically investigating the efficiency of nine energy and precious metal markets over the last decades employing several pronounced models we test for both short and the long run efficiency using in addition to linear cointegration models nonlinear cointegration and error correction models ecms which allow the efficiency intensity to change per regime our findings can be summarized as follows i futures prices are found to be cointegrated with spot prices but they do not constitute unbiased predictors of future spot prices ii the hypothesis of risk neutrality is rejected iii the short run efficiency hypothesis is rejected suggesting that using past futures price returns improves the modeling and forecasting of future spot prices and iv the nonlinear modeling suggests the presence of two distinct regimes wherein the first regime the efficiency hypothesis is supported whereas in the second it is rejected the empirical findings have important implications for producers hedgers speculators and policymakers

forecasting system imbalance volumes in competitive electricity markets forecasting in power systems has been made considerably more complex by the introduction of competitive electricity markets furthermore new variables need to be predicted by various market participants this paper shows how a new methodology that combines classical and data mining techniques can be used to forecast the system imbalance volume a key variable for the system operator in the market of england and wales under the new electricity trading arrangements neta

liberalisation consumption heterogeneity and the dynamics of energy prices in this study the methodology var and the cointegration analysis are used to examine the dynamic interaction among the energy prices of the competitor energy sources in a liberalised market data from the uk market were applied and models for the residential and industrial sectors were developed our results indicate the existence of long run relationships between the energy prices before and after the liberalisation implying the possibility of substitution among the different forms of energy however the results appear to be also largely influenced by external variables not included in the models that may be reducing the importance of the energy prices over their own evolution and offsetting the basic substitution relationships the general results of the impulse response functions both for the residential and industrial sectors present low statistical significance which seems to be due to the still slow rate of adjustment of the energy market to price changes along with the immaturity of the liberalisation process taking into consideration the results some routes for future research are pointed out namely the need to include in the analysis variables which would proxy the general state of the economy

the relationship among energy prices and energy consumption in china the pricing mechanism for energy is not in line with the international standards because the energy prices are controlled by the government partly or completely in china chinese government made a lot of efforts to improve the pricing mechanism for energy the relations between chinese energy prices and energy consumption are the foundations to reform the mechanism in this paper the relations between chinese energy consumption and energy prices are researched by cointegration equations impulse response functions granger causality and variance decomposition the cointegration relations among energy prices energy consumption and economic outputs show that higher energy price will decrease energy consumption in chinese industrial sectors but will not reduce the economic output in the long run the cointegration relation between energy price and household energy consumption shows that higher energy price will decrease household energy consumption in the long run and increase it in the short run so chinese government should deepen the reform of pricing mechanism for energy and increase the energy prices reasonably to save energy

empirical assessment of energy price policies the case for cross price elasticities abstract evaluations of energy price policies are necessarily based on measures of the substitution of energy and non energy inputs facing a variety of substitution elasticities the central question arises which measure would be appropriate apparently for a long time this question has not been at issue allen s elasticities of substitution aes have been the most used measures in applied production analysis this paper s main contribution is an instructive survey of the origin of substitution measures and of the trinity of empirical substitution elasticities aes cross price elasticities and the morishima elasticities of substitution mes with particular emphasis on their interpretations and the perspectives that will be captured by these measures this survey clarifies why classical cross price elasticities are to be preferred for many practical purposes berndt and wood s rev econom stat 57 1975 259 frequently applied data set of us manufacturing is used to illustrate why assessments of energy price policies would be better based on cross price elasticities like the energy price elasticity of capital rather than on aes or mes

arima models to predict next day electricity prices price forecasting is becoming increasingly relevant to producers and consumers in the new competitive electric power markets both for spot markets and long term contracts price forecasts are necessary to develop bidding strategies or negotiation skills in order to maximize benefit this paper provides a method to predict next day electricity prices based on the arima methodology arima techniques are used to analyze time series and in the past have been mainly used for load forecasting due to their accuracy and mathematical soundness a detailed explanation of the aforementioned arima models and results from mainland spain and californian markets are presented

a new statistic and practical guidelines for nonparametric granger causality testing abstract in this paper we introduce a new nonparametric test for granger non causality which avoids the over rejection observed in the frequently used test proposed by hiemstra and jones 1994 testing for linear and nonlinear granger causality in the stock price volume relation journal of finance 49 1639 1664 after illustrating the problem by showing that rejection probabilities under the null hypothesis may tend to one as the sample size increases we study the reason behind this phenomenon analytically it turns out that the hiemstra jones test for the null of granger non causality which can be rephrased in terms of conditional independence of two vectors x and z given a third vector y is sensitive to variations in the conditional distributions of x and z that may be present under the null to overcome this problem we replace the global test statistic by an average of local conditional dependence measures by letting the bandwidth tend to zero at appropriate rates the variations in the conditional distributions are accounted for automatically based on asymptotic theory we formulate practical guidelines for choosing the bandwidth depending on the sample size we conclude with an application to historical returns and trading volumes of the standard and poor s index which indicates that the evidence for volume granger causing returns is weaker than suggested by the hiemstra jones test

day ahead financial loss gain modeling and prediction for a generation company in an electricity market the main goal of a generation company genco is to maximize its profit while encountering the uncertainty of the electricity price forecast different risk measures have been proposed to cope with this source of uncertainty however those are usually before the fact performance indices and cannot give a measure for the financial loss gain flg of a genco considering the electricity prices actually realized in the market this paper focuses on this matter the time series of flg is first constructed given the real conditions of the electricity market then the flg time series is quantized using silhouette criterion and k means clustering approach subsequently based on the historical values of the quantized flg time series and relevant exogenous variables its day ahead values are predicted the method proposed for day ahead flg prediction consist of conditional mutual information and sequential forward search as the feature selection technique and extreme learning machine as the forecasting engine the effectiveness of the whole proposed approach including the flg time series construction quantization approach and the prediction method is shown for a typical genco using the real data of the pjm and ontario electricity markets

the response of employees to severance incentives the university of california s faculty 1991 94 in response to huge budgetary shortfalls in the early 1990s the university of california offered its older and longer service employees financial inducements to leave this paper analyzes the responses of uc s faculty to three waves of buyout incentives it is estimated that an individual presented with 10 percent higher severance benefits has a 7 8 percent higher probability of quitting however quit probabilities are very difficult to forecast with accuracy this casts doubt on arguments that maintain that buyouts are superior to employer initiated layoffs as a mechanism to effect large employment changes

world oil and agricultural commodity prices evidence from nonlinear causality abstract the increasing co movements between the world oil and agricultural commodity prices have renewed interest in determining price transmission from oil prices to those of agricultural commodities this study extends the literature on the oil agricultural commodity prices nexus which particularly concentrates on nonlinear causal relationships between the world oil and three key agricultural commodity prices corn soybeans and wheat to this end the linear causality approach of toda yamamoto and the nonparametric causality method of diks panchenko are applied to the weekly data spanning from 1994 to 2010 the linear causality analysis indicates that the oil prices and the agricultural commodity prices do not influence each other which supports evidence on the neutrality hypothesis in contrast the nonlinear causality analysis shows that i there are nonlinear feedbacks between the oil and the agricultural prices and ii there is a persistent unidirectional nonlinear causality running from the oil prices to the corn and to the soybeans prices the findings from the nonlinear causality analysis therefore provide clues for better understanding the recent dynamics of the agricultural commodity prices and some policy implications for policy makers farmers and global investors this study also suggests the directions for future studies

testing for linear and nonlinear granger causality in the stock price volume relation linear and nonlinear granger causality tests are used to examine the dynamic relation between daily dow jones stock returns and percentage changes in new york stock exchange trading volume we find evidence of significant bidirectional nonlinear causality between returns and volume we also examine whether the nonlinear causality from volume to returns can be explained by volume serving as a proxy for information flow in the stochastic process generating stock return variance as suggested by clark s 1973 latent common factor model after controlling for volatility persistence in returns we continue to find evidence of nonlinear causality from volume to returns

energy price impacts modelling in the agriculture sector abstract energy price impacts in the agriculture sector are mainly of economic and non economic types however economic impacts are well researched this paper surveys the various types of energy price impacts and different estimation techniques used in the past the study suggests that the energy price impacts estimation from a systems model of the agriculture sector is the best for several reasons for this purpose a price endogenous sectoral programming model of agriculture can be developed in a partial or general equilibrium framework however data requirements for this are enormous

are gold and silver cointegrated new evidence from quantile cointegrating regressions this paper revisits the study on the long run relationship between gold and silver by escribano and granger 1998 we apply a quantile cointegration model to gold and silver prices and to prices of the corresponding futures contracts whereas cointegration models assuming a constant cointegrating vector fail to detect a cointegration relationship between gold and silver we are able to show that a nonlinear long run relationship exits the cointegrating vector is modelled as state dependent and time varying in our framework and the quantile cointegration estimates reveal substantial asymmetry in the relationship the results suggest that the pronounced role of precious metals as investment opportunities particularly in bubble like episodes and times of financial turmoil leads to comovement of gold and silver in these periods

forecasting next day electricity prices by time series models in the framework of competitive electricity markets power producers and consumers need accurate price forecasting tools price forecasts embody crucial information for producers and consumers when planning bidding strategies in order to maximize their benefits and utilities respectively this paper provides two highly accurate yet efficient price forecasting tools based on time series analysis dynamic regression and transfer function models these techniques are explained and checked against each other results and discussions from real world case studies based on the electricity markets of mainland spain and california are presented

energy price forecasting in the ontario competitive power system market this paper introduces a method for forecasting energy prices using artificial intelligence methods such as neural networks and fuzzy logic and a combination of the two the new approach is compared with some of the exiting methods various factors affecting the market clearing price are investigated results for the ontario electricity market are presented

commodity futures and market efficiency we propose a comprehensive treatment of the leverage effect i e the relationship between returns and volatility of a specific asset focusing on energy commodities futures namely brent and wti crude oils natural gas and heating oil after estimating the volatility process without assuming any specific form of its behavior we find the volatility to be long term dependent with the hurst exponent on a verge of stationarity and non stationarity to overcome such complication we utilize the detrended cross correlation and the detrending moving average cross correlation coefficients and we find the standard leverage effect for both crude oils and heating oil for natural gas we find the inverse leverage effect additionally we report that the strength of the leverage effects is scale dependent finally we also show that none of the effects between returns and volatility is detected as the long term cross correlated one these findings can be further utilized to enhance forecasting models and mainly in the risk management and portfolio diversification

the relationship between crude oil spot and futures prices cointegration linear and nonlinear causality the present study investigates the linear and nonlinear causal linkages between daily spot and futures prices for maturities of one two three and four months of west texas intermediate wti crude oil the data cover two periods october 1991 october 1999 and november 1999 october 2007 with the latter being significantly more turbulent apart from the conventional linear granger test we apply a new nonparametric test for nonlinear causality by diks and panchenko after controlling for cointegration in addition to the traditional pairwise analysis we test for causality while correcting for the effects of the other variables to check if any of the observed causality is strictly nonlinear in nature we also examine the nonlinear causal relationships of vecm filtered residuals finally we investigate the hypothesis of nonlinear non causality after controlling for conditional heteroskedasticity in the data using a garch bekk model whilst the linear causal relationships disappear after vecm cointegration filtering nonlinear causal linkages in some cases persist even after garch filtering in both periods this indicates that spot and futures returns may exhibit asymmetric garch effects and or statistically significant higher order conditional moments moreover the results imply that if nonlinear effects are accounted for neither market leads or lags the other consistently videlicet the pattern of leads and lags changes over time

market efficiency of oil spot and futures a mean variance and stochastic dominance approach this paper examines the market efficiency of oil spot and futures prices by using both mean variance mv and stochastic dominance sd approaches based on the west texas intermediate crude oil data for the sample period 1989 2008 we find no evidence of any mv and sd relationships between oil spot and futures indices this infers that there is no arbitrage opportunity between these two markets spot and futures do not dominate one another investors are indifferent to investing spot or futures and the spot and futures oil markets are efficient and rational the empirical findings are robust to each sub period before and after the crises for different crises and also to portfolio diversification

how social security and medicare affect retirement behavior in a world of incomplete markets this paper provides an empirical analysis of how the u s social security and medicare insurance system affect the labor supply of older males in the presence of incomplete markets for loans annuities and health insurance we estimate a detailed dynamic programming dp model of the joint labor supply and social security acceptance decision focusing on a sample of males in the low to middle income brackets whose only pension is social security the dp model delivers a rich set of predictions about the dynamics of retirement behavior and comparisons of actual vs predicted behavior show that the dp model is able to account for wide variety of phenomena observed in the data including the pronounced peaks in the distribution of retirement ages at 62 and 65 the ages of early and normal eligibility for social security benefits respectively we identify a significant fraction of health insurance constrained individuals who have no form of retiree health insurance other than medicare and who can only obtain fairly priced private health insurance via their employer s group health plan the combination of significant individual risk aversion and a long tailed pareto distribution of health care expenditures implies that there is a significant security value for these individuals to remain employed until they are eligible for medicare coverage at age 65 overall our model suggests that a number of heretofore puzzling aspects of retirement behavior can be viewed as artifacts of particular details of the social security rules whose incentive effects are especially strong for lower income individuals and those who do not have access to fairly priced loans annuities and health insurance

the impacts of energy prices on energy intensity evidence from china in this paper we present a review of the deregulation of energy prices in china between 1985 and 2004 and assess the impacts of changes in energy prices on aggregate energy intensity and coal oil electricity intensity we used time series data to provide estimates of energy price elasticities empirical results showed that 1 the own price elasticities of coal oil and aggregate energy were negative in periods both before and after 1995 implying that higher relative prices of different energy types lead to the decrease in coal oil and aggregate energy intensities however the positive own price elasticity of electricity after 1995 probably indicates that the price effect was weaker than other factors such as income effect and population effect 2 the impacts of energy prices were asymmetric over time 3 sectoral adjustment also drove the decrease in aggregate energy intensity although raising energy prices to boost efficiency of energy use seems to be an effective policy tool other policy implications concerned with energy prices such as energy supply security and fuel poverty must also be considered

efficiency of crude oil markets evidences from informational entropy analysis abstract the role of crude oil as the main energy source for the global economic activity has motivated the discussion about the dynamics and causes of crude oil price changes an accurate understanding of the issue should provide important guidelines for the design of optimal policies and government budget planning using daily data for wti over the period january 1986 march 2011 we analyze the evolution of the informational complexity and efficiency for the crude oil market through multiscale entropy analysis the results indicated that the crude oil market is informationally efficient over the scrutinized period except for two periods that correspond to the early 1990s and late 2000s us recessions overall the results showed that deregulation has improved the operation of the market in the sense of making returns less predictable on the other hand there is some evidence that the probability of having a severe us economic recession increases as the informational efficiency decreases which indicates that returns from crude oil markets are less uncertain during economic downturns