answering the skeptics yes standard volatility models do provide accurate forecasts a voluminous literature has emerged for modeling the temporal dependencies in financial market volatility using arch and stochastic volatility models while most of these studies have documented highly significant in sample parameter estimates and pronounced intertemporal volatility persistence traditional ex post forecast evaluation criteria suggest that the models provide seemingly poor volatility forecasts contrary to this contention we show that volatility models produce strikingly accurate interdaily forecasts for the latent volatility factor that would be of interest in most financial applications new methods for improved ex post interdaily volatility measurements based on high frequency intradaily data are also discussed

market clearing with stochastic security part i formulation the first of this two paper series formulates a stochastic security constrained multi period electricity market clearing problem with unit commitment the stochastic security criterion accounts for a pre selected set of random generator and line outages with known historical failure rates and involuntary load shedding as optimization variables unlike the classical deterministic reserve constrained unit commitment here the reserve services are determined by economically penalizing the operation of the market by the expected load not served the proposed formulation is a stochastic programming problem that optimizes concurrently with the pre contingency social welfare the expected operating costs associated with the deployment of the reserves following the contingencies this stochastic programming formulation is solved in the second companion paper using mixed integer linear programming methods two cases are presented a small transmission constrained three bus network scheduled over a horizon of four hours and the ieee reliability test system scheduled over 24 h the impact on the resulting generation and reserve schedules of transmission constraints and generation ramp limits of demand side reserve of the value of load not served and of the constitution of the pre selected set of contingencies are assessed

a theory of intergenerational altruism modeling intergenerational altruism is crucial to evaluate the long term consequences of current decisions and requires a set of principles guiding such altruism we axiomatically develop a theory of pure direct altruism altruism is pure if it concerns the total utility rather than the mere consumption utility of future generations and direct if it directly incorporates the utility of all future generations our axioms deliver a new class of altruistic forward looking preferences whose weight put on the consumption of a future generation generally depends on the consumption of other generations the only preferences lacking this dependence correspond to the quasi hyperbolic discounting model which our theory characterizes our approach provides a framework to analyze welfare in the presence of altruistic preferences and addresses technical challenges stemming from the interdependent nature of such preferences

uncertainty management in the unit commitment problem uncertainty in power systems operations has been traditionally managed by multistage decision making and operating reserve requirements a familiar example of multistage decisions is day ahead unit commitment and real time economic dispatch an alternate approach for managing uncertainty is a stochastic formulation which allows the explicit modeling of the sources of uncertainty this paper compares stochastic and reserve methods and evaluates the benefits of a combined approach for the efficient management of uncertainty in the unit commitment problem numerical studies show that unit commitment solutions obtained for the combined approach are robust and superior with respect to the traditional approach in terms of both economics and reliability metrics

market clearing with stochastic security part ii case studies this paper analyzes the market clearing formulation with stochastic security developed in its companion paper through two case studies solved using mixed integer linear programming techniques the generation and reserve schedules as well as the nodal prices of energy and security are assessed under various conditions such as a line flow limits b when nonspinning reserve is excluded from the formulation c demand side valuation of energy not served d generator ramping limits and e the set of pre selected contingencies

incorporating fuel constraints and electricity spot prices into the stochastic unit commitment problem the electric power industry is going through deregulation as a result the load on the generating units of a utility is becoming increasingly unpredictable furthermore electric utilities may need to buy power or sell their production to a power pool that serves as a spot market for electricity these trading activities expose utilities to volatile electricity prices in this paper we present a stochastic model for the unit commitment that incorporates power trading into the picture our model also accounts for fuel constraints and prices that may vary with electricity prices and demand the resulting model is a mixed integer program that is solved using lagrangian relaxation and bender s decomposition using this solution approach we solve problems with 729 demand scenarios on a single processor to within 0 1 of the optimal solution in less than 10 minutes our numerical results indicate that significant savings can be achieved when the spot market is entered into the problem and when stochastic policy is adopted instead of a deterministic one

market reaction to public information the atypical case of the boston celtics abstract the publicly traded boston celtics limited partnership shares provide a unique means of studying the impact of information on equity prices the results of the celtics basketball games significantly affect partnership share returns trading volume and volatility controlling for the expectedvalue of the signal using betting market point spreads has little effect on these relations investors respond asymmetrically to wins and losses and playoff games have a larger impact on returns than regular season games opening prices do not fully reflect game results consistent with previous findings that significant volatility is caused by traders acting on private information

the maximum likelihood estimation of security price volatility theory evidence and application to option pricing the market requires efficient estimation of the assuming security price dynamics are governed by a diffusion process and given the publicly most available form of data this paper provides the maximum likelihood estimator of security price volatility a monte carlo simulation compares the small sample properties of this and other proposed security price volatility estimators the resultant maximum likelihood estimator of the black scholes call option price formulation is also derived for small sample sizes a monte carlo simulation study facilitates comparison with other proposed estimation procedures also the statistically most powerful confidence intervals for the blackscholes call option price are constructed we would like to thank the participants of the statistics department seminar and finance department workshop at the university of michigan for their helpful comments we are especially grateful to fred hoppe adrian tschoegl and an anonymous referee for their insightful suggestions any remaining errors are our responsibility

aggregation of heterogeneous time preferences we examine an economy whose consumers have different discount factors for utility possibly not exponential we characterize the properties of efficient allocations of resources and of the shadow prices that would decentralize such allocations we show in particular that the representative agent has a decreasing discount rate when as is usually posited all of a group s members have a constant discount rate and decreasing absolute risk aversion preferences we also identify conditions that lead the representative agent to have a rate of impatience that decreases with gross domestic product per capita

the market for equity options in the 1870s the introduction of exchange traded options in 1973 led to explosive growth in the stock options market but put and call options on equity securities have existed for more than a century prior to the listing of option contracts trading was conducted in an order driven over the counter market from 1873 to 1875 quotes for options contracts were published weekly in the commercial and financial chronicle during a period that saw extensive marketing efforts by a number of brokerage firms in this article we examine these quotes to determine why this seemingly sophisticated market existed for only a brief period in financial history in 1973 exchange traded options were introduced and for the first time a central marketplace was available for the trading of standardized option contracts in addition the creation of the options clearing corporation provided an intermediary to all contracts the volume of options traded has exploded during the past twenty three years as has our understanding of the pricing of options and other derivative securities put and call options on equity securities however have been available to american investors for more than a century following the civil war an active market in privileges the term then used for options1 developed in new york city with numerous brokerage firms offering put call and double privilege contracts this market reached the height of its activity in the period from 1873 through 1875 during that time indicative price quotes from a particular broker for options on about a dozen equity securities were generally published every saturday in the commercial and financial chronicle these quotes were placed along with the other financial data for the week including daily high and low stock prices bond prices gold prices money

forecasting financial volatilities with extreme values the conditional autoregressive range carr model we propose a dynamic model for the high low range of asset prices within fixed time intervals the conditional autoregressive range model henceforth carr the evolution of the conditional range is specified in a fashion similar to the conditional variance models as in garch and is very similar to the autoregressive conditional duration acd model of engle and russell 1998 extreme value theories imply that the range is an efficient estimator of the local volatility e g parkinson 1980 hence carr can be viewed as a model of volatility out of sample volatility forecasts using the s p500 index data show that the carr model does provide sharper volatility estimates compared with a standard garch model

three or two stage stochastic market clearing algorithm as the power industry considers moving from a deterministic paradigm to a stochastic one to clear the day ahead market in systems with significant stochastic production the following question arises how should a stochastic clearing algorithm be formulated our analyses indicate that a three stage stochastic approach is clearly superior to a two stage one to show this we propose a model that includes three stages the first one represents the day ahead market the second stage the intraday market and the third one the real time operation the objective is to clear the day ahead market but with a prognosis of the future the intraday market and the real time operation to assess the impact of the intraday market on the day ahead outcomes we compare the results obtained from the proposed model with those of a simpler but more common two stage model which represents the day ahead market and the real time operation

stochastic security constrained unit commitment this paper presents a stochastic model for the long term solution of security constrained unit commitment scuc the proposed approach could be used by vertically integrated utilities as well as the isos in electricity markets in this model random disturbances such as outages of generation units and transmission lines as well as load forecasting inaccuracies are modeled as scenario trees using the monte carlo simulation method for dual optimization coupling constraints among scenarios are relaxed and the optimization problem is decomposed into deterministic long term scuc subproblems for each deterministic long term scuc resource constraints represent fuel and emission constraints in the case of vertically integrated utilities and energy constraints in the case of electricity markets lagrangian relaxation is used to decompose subproblems with long term scuc into tractable short term mip based scuc subproblems without resource constraints accordingly penalty prices lagrangian multipliers are signals to coordinate the master problem and small scale subproblems computational requirements for solving scenario based optimization models depend on the number of scenarios in which the objective is to minimize the weighted average generation cost over the entire scenario tree in large scale applications the scenario reduction method is introduced for enhancing a tradeoff between calculation speed and accuracy of long term scuc solution numerical simulations indicate the effectiveness of the proposed approach for solving the stochastic security constrained unit commitment

expected value and chance constrained stochastic unit commitment ensuring wind power utilization this paper proposes an expected value and chance constrained stochastic optimization approach for the unit commitment problem with uncertain wind power output in the model the utilization of wind power can be adjusted by changing the utilization rate in the proposed expected value constraint meanwhile the chance constraint is used to restrict the probability of load imbalance then a sample average approximation saa method is used to transform the objective function the expected value constraint and the chance constraint into sample average reformulations furthermore a combined saa framework that considers both the expected value and the chance constraints is proposed to construct statistical upper and lower bounds for the optimization problem finally the performance of the proposed algorithm with different utilization rates and different risk levels is tested for a six bus system a revised ieee 118 bus system is also studied to show the scalability of the proposed model and algorithm

the social discount rate what discount rate should be applied to social investments it is standard to use the market interest rate thereby respecting private preferences we show that application of this revealed preference criterion rests on faith not on logic it is justified only if preferences over all choices including past choices are time invariant the conditions for this to be true are stringent under more reasonable conditions policy makers should be more patient than private citizens whose choices define the most short sighted pareto optimum

social discounting and intergenerational pareto the most critical issue in evaluating policies and projects that affect generations of individuals is the choice of social discount rate this paper shows that there exist social discount rates such that the planner can simultaneously be i an exponential discounting expected utility maximizer ii intergenerationally pareto that is if all individuals from all generations prefer one policy project to another the planner agrees and iii strongly non dictatorial that is no individual from any generation is ignored moreover to satisfy i iii if the time horizon is long enough it is generically sufficient and necessary for social discounting to be more patient than the most patient individual s long run discounting independent of the social risk attitude

the value of intra day markets in power systems with high wind power penetration in this paper the value of intra day markets in managing wind power uncertainty in competitive electricity markets is analyzed a competitive electricity market model consisting of a day ahead market and a number of intra day markets is considered real time operation adjustment is also taken into account stochastic programming is used to model decision making under wind power uncertainty numerical simulations based on two test systems are presented

present bias and collective dynamic choice in the lab we study collective decisions by time discounting individuals choosing a common consumption stream we show that with any heterogeneity in time preferences utilitarian aggregation necessitates a present bias in lab experiments three quarters of social planners exhibited present biases and less than two percent were time consistent roughly a third of subjects acted as if they were pure utilitarians and the rest chose as if they also had varying degrees of distributional concerns

welfare as equity equivalents equity or its counterpart inequity plays a fundamental role in the evaluation of social welfare in different dimensions in this paper we revisit the concept of inequity in the sense of unequal distributions across individuals time and states of the world using a unified framework that generalizes the standard expected discounted utilitarianism approach we propose a general measure of welfare as equity equivalents and a corresponding inequity index we show that allowing for different attitudes toward inequity across different dimensions covers a scope of possible inequity preferences with different interpretations we then prove that the order of aggregation across the different dimensions matters for welfare evaluations finally we show that many of the welfare theoretical approaches recently developed in the literature can be interpreted as special cases of this general framework

the economic value of volatility timing using a range based volatility model abstract there is growing interest in utilizing the range data of asset prices to study the role of volatility in financial markets in this paper a new range based volatility model was used to examine the economic value of volatility timing in a mean variance framework we compared its performance with a return based dynamic volatility model in both in sample and out of sample volatility timing strategies for a risk averse investor it was shown that the predictable ability captured by the dynamic volatility models is economically significant and that a range based volatility model performs better than a return based one

improving the parkinson method of estimating security price volatilities the author proposes a new method for estimating the volatility parameters of security prices which is an improvement of the estimation method by m parkinson 1980 the author assumes that the security prices follow the geometric brownian motion however contrary to the setting of parkinson the geometric brownian motion may have nonzero drift terms the author shows that the efficiency of his estimator is about 10 in comparison with the standard sample variance estimator since the efficiency of the estimator by parkinson is about 4 91 his estimation method may considerably improve the estimation methods already known in financial economics copyright 1992 by university of chicago press

justifying social discounting the rank discounted utilitarian approach the popular discounted utilitarian criterion for infinite horizon social choice has been criticized on the ground that it treats successive generations unfairly i propose to evaluate intergenerational welfare with a rank discounted utilitarian rdu criterion instead the criterion amounts to discounted utilitarianism on non decreasing paths but it treats all generations impartially discounting becomes the mere expression of intergenerational inequality aversion i show that more inequality averse rdu societies have higher social discount rates when future generations are better off i apply the rdu approach in two benchmark economic growth models and i prove that it promotes sustainable policies maximizing discounted utility

modeling approaches for computational cost reduction in stochastic unit commitment formulations although stochastic commitment policies provide robust and efficient solutions they have high computational costs this letter considers two modeling approaches for the reduction of their computational effort the relaxation of the integrality constraint of fast start units and the modeling of generation outages as load increments these approaches are shown to reduce the computational cost while maintaining the good properties of stochastic policies

a review of the stern review on the economics of climate change how much and how fast should we react to the threat of global warming the stern review argues that the damages from climate change are large and that nations should undertake sharp and immediate reductions in greenhouse gas emissions an examination of the review s radical revision of the economics of climate change finds however that it depends decisively on the assumption of a near zero time discount rate combined with a specific utility function the review s unambiguous conclusions about the need for extreme immediate action will not survive the substitution of assumptions that are consistent with today s marketplace real interest rates and savings rates

time consistency stationarity and time invariance a sequence of experiments documents static and dynamic preference reversals between sooner smaller and later larger rewards when the sooner reward could be immediate the theoretically motivated design permits separate identification of time consistent stationary a ndtime invariant choices at least half of the subjects are time consistent but only three quarters of them exhibit stationary choices about half of subjects with time inconsistent choices have stationary preferences these results chal lenge the view that present bias preferences are the main source of time inconsistent choices the past twenty years have seen a surge of interest in time inconsistent preferences mostly this has been motivated by psychological experiments and introspection that have suggested the existence of present bias a decision maker prefers smaller immediate reward to a larger delayed reward but when she is asked about her preferences between these two alternatives when both are equally shifted into the future her preferences are reversed although there is no inconsistency per se in her answers this behavior has been taken to suggest that when the decision maker will be asked to update her choices in the future she will generally deviate from her ex ante plans our goal in the present study is to perform a dynamic preference reversal experiment as such one is required to extend the standard framework of pref erences over temporal payments to a dated collection of such preferences this extension allows us to formally define three distinct properties stationarity im plies that ranking of temporal payments depends only on the time distance and payment distance between the alternatives time invariance assumes that the decision maker evaluates each temporal payment relative to the evaluation pe

inequality and social discounting we explore steady state inequality in an intergenerational model with altruistically linked individuals who experience privately observed taste shocks when the welfare function depends only on the initial generation efficiency requires immiseration inequality grows without bound and everyone s consumption converges to zero we study other efficient allocations in which the welfare function values future generations directly placing a positive but vanishing weight on their welfare the social discount factor is then higher than the private one and for any such difference we find that consumption exhibits mean reversion and that a steady state cross sectional distribution for consumption and welfare exists with no one trapped at misery

evaluating interconnector investments in the north european electricity system considering fluctuating wind power penetration with increasing amounts of power generation from intermittent sources like wind transmission planning has not only to account for the expected load curve but also for the stochasticity of volatile power infeeds moreover investments in power generation are no longer centrally planned in deregulated power markets but rather decided on competitive grounds by individual power companies this poses particular challenges when it comes to evaluating the benefits of increased interconnection capacities in large scale systems like the european transmission system within this article an approach is presented which allows assessing the benefits of interconnector investments in the presence of stochastic power infeed and endogenous power plant investments this model uses typical days and hours as well as recombining trees to represent both load and infeed fluctuations an application is presented covering 30 european countries and simultaneously optimizing generation investments and dispatch as well as utilization of transmission lines the model is used to evaluate the benefits of further line extensions between the european mainland and northern european countries we compute welfare gains and the distribution of these gains within a business as usual scenario up to 2030

market price uncertainty risk aversion and procurement combining contracts and open market sourcing alternatives abstract we evaluate the implications of concurrent utilization of contracts and open market arrangements by a risk averse buyer in continuous procuring of a standardized product of known demand over a specified time period the buyer being risk averse is concerned about the magnitude and uncertainty of expenses the contract price is deterministic and the market price is stochastic cases when the two price processes are exogenous and when the contract price is endogenously linked to volume of procurement and market price are examined models are developed to determine the optimal pattern of procurement from the two arrangements for specified price risk aversion and contract duration parameters the study finds that optimal procurement from market increases with contract price premium but decreases with degree of risk aversion and market price uncertainty usefulness of alternate forms of contracts when contract and market alternatives are used concurrently is discussed application of the models to hypothetical datasets compares the relative usefulness of alternate forms of integrating contract and market alternatives and of complete reliance on contract or market alternatives