on jumps and arch effects in natural resource prices an application to pacific northwest stumpage prices continuous time models of natural resource prices usually preclude the possibility of large changes jumps resulting from unexpected events to test for the presence of jumps and or arch effects we combine bounds and the monte carlo test technique to obtain finite sample level exact p values we apply this methodology to stumpage prices from the pacific northwest and find evidence of jumps and arch effects to assess the impact of neglecting jumps on the decision to harvest old growth timber we develop an autonomous infinite horizon stopping model for which we provide a new method of resolution our numerical results show the importance of modeling jumps explicitly copyright 2002 oxford university press

oil and the macroeconomy a markov state switching approach this paper analyzes the relationship between oil price shocks and postwar u s business cycle fluctuations the authors develop a generalized markov switching model of output that includes a measure of net real oil price increases and examine the capabilities of this variable to generate shifts in the mean of gdp growth and to predict transitions between dichotomous growth phases the results indicate that while the behavior of oil prices has been a contributing factor to the mean of low growth phases of output movements in oil prices generally have not been a principal determinant in the historical evidence of these phases copyright 1997 by ohio state university press

the tree cutting problem in a stochastic environment the case of age dependent growth abstract harvest policies are derived for growing biological assets e g forests livestock subject to stochastic age dependent growth and price uncertainty the task posed is analyzed as a continuous time optimal stopping problem for diffusion processes both single and ongoing rotation problems are considered qualitative comparative static and numerical results are provided

recent trends in the uk income distribution what happened and why the uk income distribution changed its shape dramatically during the 1980s this paper documents the trends and analyses their causes copyright 1996 by oxford university press

income distribution human capital and economic growth in colombia abstract colombian income distribution has followed a clear path during the last two decades in the second half of the 1970s human capital accumulation reduced the dispersion of income distribution and lead to a period of stagnation between 1983 and 1990 when mobility declined after the structural reforms a skill bias technological change the wage differential for skilled workers increased inequality by a polarization in the bi modal distribution of income these topics are discussed in the paper along some dynamic aspects of income and educational mobility in colombia

resistance to reform status quo bias in the presence of individual specific uncertainty comment why do governments so often fail to adopt policies which economists consider to be efficiency enhancing our answer to this question relies on uncertainty regarding the distribution of gains and losses from reform we show that there is a bias towards the status quo and hence against efficiency enhancing reforms whenever some of the individual gainers and losers from reform cannot be identified beforehand there are reforms which once adopted will receive adequate political support but would have failed to carry the day ex ante the argument does not rely on risk aversion irrationality or hysteresis due to sunk costs jel d72 f13 why do governments so often fail to adopt policies that economists consider to be efficiency enhancing this is one of the fundamental questions of political economy the answer usually relies on what may be

income distribution and macroeconomics this paper analyzes the role of wealth distribution in macroeconomics through investment in human capital it is shown that in the presence of credit markets imperfections and indivisibilities in investment in human capital the initial distribution of wealth affects aggregate output and investment both in the short and in the long run as there are multiple steady states this paper therefore provides an additional explanation for the persistent differences in per capita output across countries furthermore the paper shows that cross country differences in macroeconomic adjustment to aggregate shocks can be attributed among other factors to differences in wealth and income distribution across countries

option valuation and hedging strategies with jumps in the volatility of asset returns we develop a model in which the volatility of risky assets is subject to random and discontinuous shifts over time we derive prices of claims contingent on such assets and analyze options based trading strategies to hedge against the risk of jumps in the return volatility unsystematic and systematic events such as takeovers major changes in business plans or shifts in economic policy regimes may drastically alter firms risk profiles our model captures the effect of such events on options markets lumpy arrival of information has long been recognized as a phenomenon of considerable importance in financial markets following merton 1976 1 much of the literature on contingent claims valuation under discontinuous information arrival has studied the case where jumps occur in asset values in this article we model the discontinuous resolution of uncertainty in a new way we allow for the volatility of an asset s return to change randomly and discretely we then derive and analyze valuation equations for claims contingent on such an asset we also show how certain traded options together with the underlying stock and a riskless bond can be used to insure against jumps in the volatility of an asset s returns stock price movements in our model fluctuate randomly between low and high volatility regimes discontinuous changes in the volatility of stock prices may be a result of significant changes in a firm s operating and financial structure its competitive environment or its corporate plan reorganizations caused by takeovers and mergers may also occasion such volatility shifts changes in uncertainty in our model could also be systematic and a result of aggregate supply shocks or shifts in economic policies and political regimes our model can also be interpreted as a model of a market where from time to time firms face the release of an important piece of information that may affect their stock prices significantly the market participants may be aware

short term variations and long term dynamics in commodity prices in this article we develop a two factor model of commodity prices that allows meanreversion in short term prices and uncertainty in the equilibrium level to which prices revert although these two factors are not directly observable they may be estimated from spot and futures prices intuitively movements in prices for long maturity futures contracts provide information about the equilibrium price level and differences between the prices for the short and long term contracts provide information about short term variations in prices we show that although this model does not explicitly consider changes in convenience yields over time this short term long term model is equivalent to the stochastic convenience yield model developed in gibson and schwartz 1990 we estimate the parameters of the model using prices for oil futures contracts and apply the model to some hypothetical oil linked assets to demonstrate its use and some of its advantages over the gibson schwartz model

inequality income growth and mobility the basic facts during the 1950s and 1960s mean wages in the united states grew rapidly and the dispersion around this growing mean changed very litde starting in the 1970s and continuing into the 1980s and 1990s these patterns were reversed mean wages grew slowly and inequality increased rapidly these changes in labor markets were reflected in changes in the distribution of family income the mean of the distribution of family income did increase after 1973 in spite of the near constancy of mean real wages as family members increased the number of hours they worked however the increase in inequality of wages was mirrored by an increase in the dispersion of family income a large descriptive literature has documented the rise in inequality while a smaller behavioral literature has sought to delineate the causes of this rise these changes in the distribution of family income a fected rates of poverty directly during the 1950s and 1960s temporary increases in poverty during recessions were more than offset by declines in poverty during economic expansions as long as the poor gained along with everyone else fi om the secular growth in the mean one could be confident that poverty rates would ratchet down this is exactly what happened as poverty rates fell from 22 4 percent in 1959 to 11 1 percent in 1973

taxation and rotation age under stochastic forest stand value abstract the paper uses both the single rotation and ongoing rotation framework to study the impact of yield tax lump sum tax and tax on interest rate earnings on the privately optimal rotation period when forest stand value is stochastic and forest owners are risk averse or risk neutral under risk aversion the optimal harvesting threshold is lower and therefore the expected rotation period shorter than under risk neutrality both in the single and ongoing rotation cases whether the forest owner is risk averse or risk neutral a higher yield tax a higher lump sum tax or a higher tax on interest rate earnings raise the optimal harvesting threshold numerical results indicate that the optimal harvesting threshold increases less rapidly under risk aversion than under risk neutrality with an increase in either a yield tax or the volatility of forest stand value

regime switching in stochastic models of commodity prices an application to an optimal tree harvesting problem abstract this paper investigates whether a regime switching model of stochastic lumber prices is better for the analysis of optimal harvesting problems in forestry than a more traditional single regime model prices of lumber derivatives are used to calibrate a regime switching model with each of two regimes characterized by a different mean reverting process a single regime mean reverting process is also calibrated the value of a representative stand of trees and optimal harvesting prices are determined by specifying a hamilton jacobi bellman variational inequality which is solved for both pricing models using a implicit finite difference approach the regime switching model is found to more closely match the behavior of futures prices than the single regime model in addition analysis of a tree harvesting problem indicates significant differences in terms of land value and optimal harvest thresholds between the regime switching and single regime models

contraception as development new evidence from family planning in colombia there has been considerable debate in the last decade about whether or not family planning programmes in developing countries reduce fertility or improve socio economic outcomes this article provides new evidence by studying the expansion of one of the worlds oldest and largest family planning organisations profamilia of colombia it finds that family planning explains less than 10 of colombias fertility decline during its demographic transition as in wealthy countries however lowering the costs of first birth postponement produced important socio economic gains enabling young women to obtain more education and to work more and live independently later in life

the valuation of forestry resources under stochastic prices and inventories a contingent claims approach to capital budgeting may be preferable to traditional methods where uncertainty and managers strategic reactions to changing conditions are impor tant as an example of such a case we solve the classical problem of the duration of an investment in forestry resources i e when to cut down the trees in the general case of stochastic output prices and stochastic natural growth rate and timber inventories a con tingent claims approach is used to value the forestry resources as a function of 1 sto chastic prices and inventories and 2 an asymmetric optimal production policy that incorporates the option to halt timber production temporarily i introduction classical capital budgeting techniques are based on the assumption that fu ture cash flows follow a rigid pattern and can be accurately predicted far into the future on the basis of such cash flow predictions the project is either accepted or rejected the uncertainty in the project and management s strategic reactions to changing conditions are dealt with only superficially at best a risk adjusted interest rate is employed and various deterministic scenarios are plotted out in situations where uncertainty and management s strategic reactions to it are im portant the classical technique is apt to lead to wrong decisions the technology needed to deal with such problems more accurately is becoming available the purpose of this paper is to present a stylized example of how it can be used our example is a general solution to the classical duration problem of the optimal control of a long term renewable resource investment such as forestry resources i e when to chop down a tree 1 if the prices and the natural growth rate of the inventory of forest timber are assumed to be deterministic the optimal control is very simple to derive but when both the price and inventory of timber are stochastic the problem becomes both stochastic and asymmetric the asym

the hamilton model with a general autoregressive component estimation and comparison with other models of economic time series abstract this paper generalizes the hamilton model to the important case in which the autoregressive component need not contain a unit root using u s quarterly real gnp data the model is estimated and the results are compared to those of hamilton some monte carlo evidence for the model is presented and its in sample forecasting performance is discussed and compared to the original hamilton model the arima model and the deterministic time trend model

harvest decisions and asset valuation for biological resources exhibiting size dependent stochastic growth optimal harvest rules and preharvest valuation procedures are derived for biological assets with stochastic size dependent growth in a stochastic price environment these issues are analyzed as continuous time optimal stopping problems both the single rotation and ongoing rotations problems are addressed the sensitivity of harvest and valuation rules is assessed the results are compared with those derived from a myopic look ahead procedure and with the corresponding findings for age dependent growth copyright 1990 by economics department of the university of pennsylvania and the osaka university institute of social and economic research association

optimal leverage for the utility maximizing firm abstract this paper investigates the behavior of a utility maximizing firm which chooses both its financial structure and its technique of production risk attitudes affect the production choice only indirectly risk aversion shifts the demand curve for credit this demand shift affects the marginal interest rate faced by the firm and through the interest rate there is an effect on production interaction of credit supply and demand schedules may segment the population into groups with very different responses to risk or credit market policy interventions

mean reversion in equilibrium asset prices evidence from the futures term structure we use the term structure of futures prices to test whether investors anticipate mean reversion in spot asset prices the empirical results indicate mean reversion in each market we examine for agricultural commodities and crude oil the magnitude of the estimated mean reversion is large for example point estimates indicate that 44 percent of a typical spot oil price shock is expected to be reversed over the subsequent eight months for metals the degree of mean reversion is substantially less but still statistically significant we detect only weak evidence of mean reversion in financial asset prices in this study we provide evidence of mean reversion in the prices of several real and financial assets rather than examining evidence of ex post reversion using time series of asset prices we use price data from futures contracts with varying delivery horizons to test whether investors expect asset prices to revert this approach offers two advantages first since futures prices are readily available for many markets our procedure can be implemented for many assets including those for which reliable spot price data is elusive second there is little ambiguity as to the source of any mean reversion detected using our method subject only to the maintained assumption that the no arbitrage cost of carry condition holds our test detects mean reversion that is expected to occur in equilibrium but has no power to detect mean reversion resulting from noise or inefficiencies our methodology focuses on relations between price levels and the slope of the futures term structure defined as the change across delivery dates in the futures prices observed on a given trading date an inverse relation between prices and the futures term slope constitutes evidence that investors expect mean reversion in spot prices to illustrate initially assume there are no

optimal forest rotation when stumpage prices follow a diffusion process a key assumption in the faustmann rule for financial maturity is that stumpage prices are constant over time timber price series however exhibit wide fluctuations over time which this paper models as a lognormal diffusion process comparing the diffusion results modeled here to the fixed price faustmann results show 1 the prescribed rotation length is generally longer 2 computed stand values are higher using the diffusion model with the greatest divergence occurring when a stand is about the midpoint of a rotation 3 as the stumpage price volatility increases the gain in computed npv increases though in a nonlinear fashion

technological progress mobility and economic growth this paper analyzes the relationship between technological progress wage inequality intergenerational earnings mobility and economic growth in periods of major technological inventions a decline in the relative importance of initial conditions raises inequality enhances mobility and generates a larger concentration of high ability individuals in technologically advanced sectors stimulating future technological progress and growth however once technologies become more accessible mobility is diminished and inequality decreases but becomes more persistent the reduction in the concentration of ability in technologically advanced sectors diminishes the likelihood of technological breakthroughs and slows future growth user friendliness therefore becomes unfriendly to future economic growth copyright 1997 by american economic association

markup pricing in mergers and acquisitions this paper studies the relation between the premiums in takeover bids involving exchange listed target firms from 1975 91 and the pre announcement stock price runups the evidence shows that the pre bid runup and the postannouncement increase in the target s stock price the markup are generally uncorrelated with little substitution between the runup and the markup the runup is an added cost to the bidder this finding has important implications for assessing the costs of insider trading it also raises interesting questions about the role of information from public capital markets in private takeover negotiations

valuing oil properties integrating option pricing and decision analysis approaches there are two major competing procedures for evaluating risky projects where managerial flexibility plays an important role one is decision analytic based on stochastic dynamic programming and the other is option pricing theory or contingent claims analysis based on the no arbitrage theory of financial markets in this paper we show how these two approaches can be profitably integrated to evaluate oil properties we develop and analyze a model of an oil property either a developed property or a proven but undeveloped reserve where production rates and oil prices both vary stochastically over time and at any time the decision maker may terminate production or accelerate production by drilling additional wells the decision maker is assumed to be risk averse and can hedge price risks by trading oil futures contracts we also describe extensions of this model that incorporate additional uncertainties and options discuss its use in exploration decisions and in evaluating a portfolio of properties rather than a single property and briefly describe other potential applications of this integrated methodology

on solving the multirotational timber harvesting problem with stochastic prices a linear complementarity formulation this article develops a two factor real options model of the harvesting decision over infinite rotations assuming a known stochastic price process and using a rigorous hamilton jacobi bellman methodology the harvesting problem is formulated as a linear complementarity problem that is solved numerically using a fully implicit finite difference method this approach is contrasted with the markov decision process models commonly used in the literature the model is used to estimate the value of a representative stand in ontario s boreal forest both when there is complete flexibility regarding harvesting time and when regulations dictate the harvesting date