monetary policy macro stability and growth there is greater appreciation now amongst economists of the negative effect of uncertainty on investment growth and equality especially when credit constraints are widespread this implies an important linkage between the transparency and predictability of the policy environment and growth and equality the paper begins with a literature survey on the inflation and inflation volatility link the uncertainty and investment link and the inflation volatility and growth link this framework is used to examine the experience of south africa s new monetary policy regime inflation targeting it in achieving greater macrostability south africa is an interesting case study being one of the more advanced of the emerging markets with its deep and sophisticated financial system and yet with around 35 percent unemployment and a legacy of developmental problems from the apartheid era the authors demonstrate using evidence from three sources of micro data that the new monetary regime is more credible transparent and predictable they examine the performance of monetary policy and argue it has not resulted in real interest rate levels that are a hindrance to growth they explore the better response under it to big external shocks like exchange rate depreciation as compared with the monetary regime prior to it the paradox is examined of success in achieving macro stability where greater household acquisition of debt and increased demand is both inflationary and limits saving hence constraining corporate investment the paper concludes with lessons from south africa s recent successful monetary policy experience for other emerging market countries and for less developed countries central banks e g in africa

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

to value or not to value that is not the question abstract should we reject money when we value nature like most environmentalists ecological economists are increasingly divided on this question synthesizing political ecology with ecological economics we argue that this way of framing the question is limited we propose a reformulation of the question into when and how to value with money and under what conditions we recommend four criteria for a sound choice environmental improvement distributive justice and equality maintenance of plural value articulating institutions and confronting commodification under neo liberalism we call for due attention to the socio political context within which a valuation is placed and the political goals it serves the relevance of this framework is demonstrated by applying it to three practical cases pollution damages water pricing and payments for ecosystem services

the role of spatial scale in the timing of uncertain environmental policy the spatial scale of an environmental problem is dictated by boundaries physical boundaries limit the extent of impacts while the scale of decision making creates perceived boundaries beyond which impacts are ignored by decision makers while it is well understood that uncertainty and irreversibility will alter policy decisions aimed at alleviating environmental impacts the effect of spatial scales both physical and perceived is less understood when spatial scale is included in a real options model of environmental policy adoption results indicate that the importance and influence of spatial considerations depends on the level of uncertainty stringency of the proposed policy and flexibility of the policy decision recognizing spatial scale may force policy adoption to take place within a window of current damage when spatial scale is small or uncertainty high this window for policy adoption can close precluding policy adoption entirely this undermines well known results demonstrating that changes in uncertainty will only alter the timing of policy adoption in other instances the policy adoption window remains open but the option value increases faster than the benefits of the policy creating a scenario where it is always preferable to delay here the inclusion of an option value can prevent adoption of policies that would be adopted according to traditional cost benefit analysis in general policy decisions will be most affected by spatial considerations when the spatial scale is small damage is spreading fast and the uncertainty in damage spread is high

trends in the development of ecological economics from the late 1980s to the early 2000s abstract as the contributions to ecological economics are very diverse recent years have seen some discussion on both how to delimit the field and in which direction it should develop the intention with this paper is to contribute to the discussion by outlining important trends in the development of the field from the late 1980s to the early 2000s the study is inspired by other studies in the sociology and history of science in particular by the theoretical framework regarding scientific fields as reputational organizations which draws attention to both cognitive and social aspects of the formation of a field the basis for the paper is a combination of literature studies interviews with key researchers in the field and participant observations the paper outlines the characteristic cognitive features of ecological economics at the time of the birth of the field it is then described how the development in ecological economics was influenced by broader social factors during the following years and how the field was shaped by the inflow and outflow of different groups of researchers the emergence of different research programmes is outlined as is the organizational development finally the characteristics of ecological economics are summarized and the future prospects are briefly assessed

carbon subsidies taxes and optimal forest management we consider the effect of carbon credit payment schemes on forest owners land use and harvest decisions we study two possible credit allocation regimes one where credits are allocated according to the actual amount of carbon sequestered by the trees on a piece of land and another where credits are allocated according to the long run potential to sequester carbon on the land using a real options model with uncertain future timber prices we examine the effect on the timing of harvests and the replanting abandonment decision we show that both schemes discourage deforestation compensating growers for actual carbon sequestration leads to longer rotation periods between harvests while basing compensation only on the long run potential level of sequestration induces shorter rotation periods the former scheme leads to greater benefits of carbon sequestration at lower cost than the latter scheme although inducing moderate levels of sequestration is expensive under both schemes the cost falls dramatically when the level of payments climbs above some threshold indeed providing the payments are sufficiently generous carbon credit payment schemes offer an effective means of increasing carbon sequestration

critique and transformation on the hypothetical nature of ecosystem service value and its neo marxist liberal and pragmatist criticisms abstract ecosystem service valuation esv attempts to transform the opposition of human economic necessity and ecological conservation by valuing the latter in terms of the services rendered by the former however despite a number of esv inspired sustainability initiatives since the 1990s global ecological degradation continues to accelerate this suggests that esv has fallen far short of its goals of sustainable social transformation a failure which has generated considerable criticism this paper reviews three prominent lines of esv criticism 1 the neo marxist criticism which emphasizes the fictitious character of ecosystem commodities 2 the liberal criticism through friedrich hayek s concept scientistic objectivism and 3 the pragmatist criticism of value monism although each form of criticism provides insight into the limitations of esv all share esv s inability to discern what kind of social transformation is possible unable to provide an account of their own immersion in social and historical context these approaches operate in the hypothetical in light of these shortcomings this paper advances a critical theory approach which we contend provides conceptual tools uniquely well suited to more adequately address the question of social transformation

forest valuation under the new zealand emissions trading scheme a real options binomial tree with stochastic carbon and timber prices under the new zealand emissions trading scheme forests planted on or after january 1 1990 earn carbon credits these credits have to be repaid when the forest is harvested this paper analyses the effects of this scheme on the value of bareland on which radiata pine is to be planted a real options method is developed and applied assuming stochastic carbon and timber prices we find that land value increases by about 73 with the optimal rotation age substantially lengthened the derived optimal harvest price thresholds are useful in deciding whether to harvest or to wait jel q23 q28

smooth pasting as rate of return equalization abstract we further elucidate the smooth pasting condition behind optimal early exercise of options it is easy to show that smooth pasting implies rate of return equalization between the option and the levered position that results from exercise this yields new economic insights into the optimal early exercise condition that the option holder faces

optimal adaptive price search consider the problem of a consumer desiring to buy a good which is sold at a variety of prices such a buyer will be able to obtain a sequence of price quotations from various sellers when should the buyer stop searching for a lower price if he continues he may obtain a lower price but he incurs additional time effort and expense in searching the optimal price search decision is one of balancing the expectation of a possibly lower price obtained by continued search against cumulative costs from search when the prices arise from a known probability distribution the optimal search strategy has certain well defined and desirable properties in the more realistic case that the buyer has only partial information about the price distribution and must update his beliefs after observing prices in the marketplace the problem becomes more complex and search strategies become less well behaved the major purpose of this article is to determine new conditions under which optimal policies have these desirable characteristics in the case where the consumer possesses only incomplete information about the distribution of prices price quotations he receives in addition to providing him with price possibilities provide him with information about that distribution rothschild 151 in citing an unpublished paper of gastwirth has noted that small specification errors for an assumed distribution can lead to substantial changes in expected number of searches and expected cost consequently the assumption of a known distribution of prices can have a profound effect on total cost 1 0022 053 l 8 l 040001 20 02 00 o

payments for ecosystem services as commodity fetishism abstract payments for ecosystem services pes economically reward resource managers for the provision of ecosystem services and are thus characterised by i an ecological function subject to trade ii the establishment of a standard unit of exchange iii and supply demand and intermediation flows between those who sell and buy ecosystem services this paper departs from the term commodity fetishism broadly understood as the masking of the social relationships underlying the process of production to illuminate three invisibilities in the commodification of ecosystem services firstly we argue that narrowing down the complexity of ecosystems to a single service has serious technical difficulties and ethical implications on the way we relate to and perceive nature secondly the commodification of ecosystem services denies the multiplicity of values which can be attributed to these services since it requires that a single exchange value is adopted for trading finally we suggest that the process of production exchange and consumption of ecosystem services is characterised by power asymmetries which may contribute to reproducing rather than addressing existing inequalities in the access to natural resources and services

economic valuation of the vulnerability of world agriculture confronted with pollinator decline there is mounting evidence of pollinator decline all over the world and consequences in many agricultural areas could be significant we assessed these consequences by measuring 1 the contribution of insect pollination to the world agricultural output economic value and 2 the vulnerability of world agriculture in the face of pollinator decline we used a bioeconomic approach which integrated the production dependence ratio on pollinators for the 100 crops used directly for human food worldwide as listed by fao the total economic value of pollination worldwide amounted to 153 billion which represented 9 5 of the value of the world agricultural production used for human food in 2005 in terms of welfare the consumer surplus loss was estimated between 190 and 310 billion based upon average price elasticities of 1 5 to 0 8 respectively vegetables and fruits were the leading crop categories in value of insect pollination with about 50 billion each followed by edible oil crops stimulants nuts and spices the production value of a ton of the crop categories that do not depend on insect pollination averaged 151 while that of those that are pollinator dependent averaged 761 the vulnerability ratio was calculated for each crop category at the regional and world scales as the ratio between the economic value of pollination and the current total crop value this ratio varied considerably among crop categories and there was a positive correlation between the rate of vulnerability to pollinators decline of a crop category and its value per production unit looking at the capacity to nourish the world population after pollinator loss the production of 3 crop categories namely fruits vegetables and stimulants will clearly be below the current consumption level at the world scale and even more so for certain regions like europe yet although our valuation clearly demonstrates the economic importance of insect pollinators it cannot be considered as a scenario since it does not take into account the strategic responses of the markets

on the monetary macro dynamics of colombia and mexico abstract this paper investigates the dynamic interrelationship among money growth inflation and output growth for colombia and mexico on the basis of implementation of a vector autoregression methodology the evidence for colombia generally shows autonomous output growth and money growth behavior and an important role for money shocks in accounting for variations in inflations a different pattern of results emerged for mexico there are strong two way feedbacks among money growth and inflation and a less autonomous output growth behavior than in colombia

options uncertainty and sunk costs an empirical analysis of land use change abstract in a real option model of land conversion incorporating return uncertainty and sunk costs optimal conversion thresholds are significantly higher than those from expected net present value models not accounting for these factors empirical tests of conversion from agriculture to forest suggest that landowners value the option to convert when making conversion decisions higher uncertainty in returns to all potential uses and lower correlation between shocks to agricultural and forest returns decreases the likelihood of conversion estimates indicate a significant impact on conversion decisions with approximations of option values ranging from 7 to 81 of the expected value of the land asset

the optimal production of an exhaustible resource when price is exogenous and stochastic this paper examines the optimal production of a resource such as oil when its price is determined exogenously e g by a cartel such as opec and is subject to stochastic fluctuations away from an expected growth path we first examine the dependence of production on extraction cost and show that the conventional exponential decline curve is indeed optimal if marginal cost is constant with respect to the rate of extraction but is a hyperbolic function of the reserve level we next show that uncertainty about future price affects the optimal production rate in two ways first if marginal cost is a convex concave function of the rate of production stochastic fluctuations in price raise lower average cost over time so that there is an incentive to speed up slow down production second the option value of the reserve i e the ability to withhold production indefinitely and never incur the cost of extraction provides an incentive to slow down the rate of production

where is the value in valuing pollination ecosystem services to agriculture abstract current national and global scale monetary valuation of pollination services do not accurately estimate the contribution of wild pollinators to agricultural production first ecosystem wild pollination services remain largely bundled with those of managed pollinators this problem is compounded by the fact that the dependency of crops on pollination a key parameter used in current valuations does not reflect variation in pollinator density crop cultivars and growing conditions that exist in practice over half of the 153 billion of estimated global pollination service value in 2005 is based on estimates of pollinator dependency from crops with fewer than three field studies that measure actual levels of pollinator activity and corresponding fruit set the resulting uncertainty may be most distorting when applied to widely planted intensive oilseed crops furthermore current valuations are underpinned by simplistic assumptions regarding the likelihood of pollinator decline and the impact on agricultural prices although efforts to motivate wild pollinator protection through their ecosystem service value remain highly circumscribed by conceptual and empirical limitations we identify the need to go beyond technical solutions and develop a critical framework that could account for why pollinator conservation has come to be predominantly justified in these terms to begin with

asset retirement with infinitely repeated alternative replacements harvest age and species choice in forestry abstract at what age should productive assets be retired how should replacements be chosen when they differ in their uncertain ability to generate future incomes as a particular version of that problem we study the tree harvesting decision with two possible replacement species whose values as timber are stochastic and whose growth functions are deterministic in the single rotation wicksell problem starting with a bare piece of land an empty shop it is optimal to choose and plant one species immediately if its current value is sufficiently high relative to that of the other species the alternative equipment however if the species are insufficiently price differentiated it is preferable to leave the land vacant the shop empty despite the opportunity cost of doing so in the repeated version of the problem it is never optimal to leave the land bare provided the cost of replacement is null furthermore the optimal harvest tree retirement age not only depends on the price and current productivity of the trees in place but also on the price and productivity of the other species because it may replace the current one the harvest age reaches a peak at some critical threshold of the relative price that signals the necessity to switch to the alternative species indeed this is when the opportunity cost of choosing one alternative replacement over the other is the highest the land value and also the value of the firm is similar to an american option with free boundary infinite expiry period and endogenous payoff the paper highlights the opportunity cost of alternative replacement options and the central role of their volatility in both asset retirement and replacement choice decisions all results are derived analytically a numerical treatment by the penalty method completes the resolution

estimating the influence of u s ethanol policy on plant investment decisions a real options analysis with two stochastic variables abstract u s ethanol policies have contributed to changes in the levels and the volatilities of revenues and costs facing ethanol firms the implications of these policies for optimal investment behavior are investigated through an extension of the real options framework that allows for the consideration of volatility in both revenue and cost components as well as the correlation between them the effects of policy affecting plant revenues dominate the effects of those policies affecting production costs in the absence of these policies much of the recent expansionary periods would have not existed and market conditions in the late 1990s would have led to some plant closures we also show that regardless of plant size u s ethanol policy has narrowed the distance between the optimal entry and exit curves implying a more narrow range of inactivity and indicative of a more volatile evolution for the industry than would have existed otherwise

wicksellian theory of forest rotation under interest rate variability abstract we apply the wicksellian single rotation framework to cover the unexplored case of variable and stochastic interest rate we provide a mathematical characterization of the two dimensional optimal stopping problem and show in the presence of amenity valuation that increased interest rate volatility lengthens the optimal rotation period and increases the value of the optimal policy by modelling the interest rate as a mean reverting process and forest value as a geometric brownian motion and abstracting from amenity valuation we present an explicit solution for the problem numerical illustrations indicate that interest rate volatility has a significant and non linear impact on optimal rotation

a stochastic analysis of the tree paradigm abstract the tree paradigm which is a problem in optimal stopping has important ramifications for human capital acquisition search behavior firm entry and in the theory of renewable resources our paper extends previous work in the stochastic literature on several fronts we exhibit a tractable solution to the rotation problem for the stochastic model analyze the effects of inputs which control the growth process and illustrate our results with a multi stage learning problem

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

non renewability in forest rotations implications for economic and ecosystem sustainability abstract the forest rotations problem has been considered by generations of economists fisher 1930 boulding 1966 samuelson 1976 traditionally the forest resource across all future harvest periods is assumed to grow without memory of past harvest periods this paper integrates economic theory and intertemporal ecological mechanics linking current harvest decisions with future forest growth financial value and ecosystem health results and implications of a non renewable forest resource and the influence of rotation length and number on forest recovery are reported cost estimates of moving from short term economic rotations to long term ecological rotations suggest the level of incentive required for one aspect of ecosystem management a net private cost of maintaining ecosystem health emerges and for public policy purposes can be compared with measures of non timber amenity values and social benefits exhibiting increasing returns to rotation length

good timing the economics of optimal stopping abstract this paper presents an economic interpretation of the optimal stopping of perpetual project opportunities under both certainty and uncertainty prior to stopping the expected rate of return from delay exceeds the rate of interest the expected rate of return from delay is the sum of the expected rate of change in project value and the expected rate of change in the option premium associated with waiting at stopping the expected rate of return from delay has fallen to the rate of interest viewing stopping in this way unifies the theoretical and practical insights of the theory of stopping under certainty and uncertainty

a markup interpretation of optimal investment rules we re examine the basic investment problem of deciding when to incur a sunk cost to obtain a stochastically fluctuating benefit the optimal investment rule satisfies a trade off between a larger versus a later net benefit we show that this trade off is closely analogous to the standard trade off for the pricing decision of a firm that faces a downward sloping demand curve we reinterpret the optimal investment rule as a markup formula involving an elasticity that has exactly the same form as the formula for a firm s optimal markup of price over marginal cost this is illustrated with several examples consider what is probably the most basic irreversible investment problem a project can be undertaken that requires a sunk cost c and yields a benefit v the cost is known and constant over time but the benefit measured as the present value at the time the cost is incurred fluctuates as an autonomous markov process vt with continuous sample paths time is continuous and

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

tests of the relation between money and output in the real business cycle model abstract the paper contains tests of the relation between money and output implied by a real business cycle model the tests control for a variety that may affect economic growth and the growth rates of monetary aggregates using u s data from 1953 1 1984 4 we find almost no evidence that the empirical relations between real growth and measures of monetary policy violate the restrictions imposed by the model changes in a set of real variables explain a majority of the variation in gnp growth however substantial variation in gnp growth remains unexplained by the real factors that we consider

harvesting a renewable resource under uncertainty abstract this paper presents a theory of harvesting that allows for partial harvests and accounts for the risk of extinction for biological assets with size dependent stochastic growth the harvesting decision is formulated as a disinvestment problem in continuous time and generalized faustmann formulas are derived the probability of extinction is then analyzed for a wide class of growth functions an illustration based on the logistic brownian motion shows that both optimal biomass at harvest and harvest size do not vary monotonically with uncertainty more generally this paper illustrates the importance of properly accounting for barriers in stochastic investment problems

ecology and valuation big changes needed abstract ecological economics has developed as a transdisciplinary science but it has not taken significant steps toward a truly integrated process of evaluating anthropogenic ecological change the emerging dominance within ecological economics of the movement to monetize ecological services when combined with the already well entrenched dominance of contingent pricing as a means to evaluate impacts on amenities has created a monistic approach to valuation studies it is argued that this monistic approach to evaluating anthropogenic impacts is inconsistent with a sophisticated conception of ecology as a complex science that rests on shifting metaphors an alternative pluralistic and iterative approach to valuation of anthropogenic ecological change is proposed

the stochastic rotation problem a generalization of faustmann s formula to stochastic forest growth abstract in the present paper we study the optimal cutting strategy 1 2 for an ongoing forest by using stochastic impulse control we show how faustmann s formula can be generalized to stochastic growing forests the paper extends and clarifies previous studies by miller and voltaire 1983 clarke and reed 1989 and reed and clarke 1990

principles of stochastic dynamic optimization in resource management the continuous time case abstract a wide range of problems in economics agriculture and natural resource management have been analyzed using continuous time optimal control models where the state variables change over time in a stochastic manner using a firm level investment model and a model of environmental degradation this paper provides a concise introduction to continuous time stochastic control techniques the process used to derive the differential of a stochastic process is stressed and in turn is used to explain ito s lemma bellman s equation the hamilton jacobi equation the maximum principle and the expected dynamics of choice variables a basic extension of the dynamic duality literature is also provided where the hamilton jacobi equation is used to derive a stochastic and dynamic analogue of hotelling s lemma

the quantification and valuation of ecosystem services article i nfo article history received 7 august 2010 accepted 16 october 2010 this paper explores differences between economic and ecological criteria for identifying measuring and evaluating ecosystem services it argues that economic stakeholders user groups generally do well in identifying these services and assigning prices to them these prices arise spontaneously in and serve to coordinate market activity related to the environment the relevant ecological information which markets gather and apply tends to be dispersed contingent particular local transitory and embedded in institutions and practices ecologists and other scientists in contrast often seek to understand how ecosystems work and which populations and processes provide ecosystem services the knowledge science seeks unlike the information markets gather tends to be centralized collaborative collective and consensus based science pursues concepts and principles that are timeless and general rather than ephemeral and site specific the paper contrasts the dispersed and decentralized information organized by markets with the collective and centralized knowledge characteristic of science the paper argues that the conceptual distance between market based and science based methods of assembling information and applying knowledge defeats efforts to determine the value of ecosystem services in any integrated sense

the political economy of food the rise and fall of the postwar international food order the widespread perception of a food crisis since the early 1970s reflects a real turning point in the global structure of production and distribution of food grains scarcity is always an aspect of capitalist relations but its specific form is determined historically through the international food order the latter is a stable set of complementary state policies whose implicit coordination creates specific prices relative to other prices a specific pattern of specialization and resulting patterns of consumption and trade the social consequences of those orderly international arrangements make sense within a marxist conception of accumulation and class formation on a world scale i present a historical analysis of the rise of an international food order after world war ii whose principal axis was food aid from the united states to formerly self sufficient agrarian societies this order had contradictory effects both economic and political leading to a reorganization of aid and trade higher prices

carbon markets 15 years after kyoto lessons learned new challenges abstract carbon markets are substantial and they are expanding there are many lessons from market experiences over the past eight years there should be fewer free allowances better management of market sensitive information and a recognition that trading systems require adjustments that have consequences for market participants and market confidence moreover the emerging market architecture features separate emissions trading systems serving distinct jurisdictions and a variety of other types of policies exist alongside the carbon markets this situation is in sharp contrast to the top down integrated global trading architecture envisioned 15 years ago by the designers of the kyoto protocol and raises a suite of new questions in this new architecture jurisdictions with emissions trading have to decide how whether and when to link with one another stakeholders and policymakers must confront how to measure the comparability of efforts among markets as well as relative to a variety of other polic

informational efficiency of markets for stumpage comment in a study of the information efficiency of markets for stumpage in the southern united states washburn and binkley found that time series data on stumpage price if given on annual or quarterly bases reveal weak form information efficiency for stumpage markets from this they conclude that there can be no gain from using past price movements to play the market in timing timber harvests p 403 specifically they infer that the reservation price rules derived for optimal forest harvesting by norstrom lohmander and brazee and mendelsohn are not applicable to the management of southern pine timberlands

on the elasticities of harvesting rules abstract in this paper we rank the relative importance of the exogenous parameters upon the optimal harvesting size in a stochastic rotation problem we show that when the tree growth follows geometric brownian motion the harvesting size is most elastic to the harvesting cost followed by the interest rate and is least elastic to the parameters of tree growth similar ranking holds for the linear growth case in both cases the harvesting size is increasing and concave in the harvesting cost bounded between two parallel lines the harvesting decision is made according to a stochastic extension of the faustmann formula

committees with supermajority voting yield commitment with flexibility abstract a fundamental problem for government is how to combine commitment to certain policies with the flexibility required to adjust them when needed rogoff 1985 rogoff k 1985 the optimal degree of commitment to an intermediate monetary target q j econ 100 4 1169 1189 showed that a way to strike the right balance is to appoint an optimally conservative policy maker in real life however policy makers also have power over decisions where optimal plans are time consistent so delegating to a conservative person could be undesirable a flexible delegation device can be found in a large committee of randomly appointed members voting over policy after observing a shock when facing dynamic inconsistency under a single crossing property there exists a supermajority rule that implements the population median s optimally conservative policy maker with certainty another single crossing property guarantees that if simple majority voting is used to select the voting rule that will govern policy choice the supermajority preferred by the median is chosen for problems where dynamic inconsistency vanishes the committee will choose to make decisions by simple majority implementing median outcomes an application to monetary policy is developed we show that the optimal supermajority is higher when dynamic inconsistency is more severe when preferences are more homogeneous and when the economy is less volatile

the early development of monetary policy rules the view from geneva in the 1920s abstract the research programme developed by economists at the ilo in the 1920s constitutes a substantive precursor to modern discussions on the role of monetary policy and the status of the price stability norm in particular a combination of theory and empirical work formed the basis of a monetary approach to the business cycle developed in geneva the proposed policy of price level stabilisation presumed that an elastic target of price stability was a necessary condition for eventual high and stable employment the instruments indicator variables and rules of the proposed regime are examined the geneva economists founded their arguments on among other things politically independent but internationally collaborative central banks and consistent use of a range of data sources in the conduct of monetary policy over time the reputation and credibility of monetary authorities would then be enhanced in the evolution of the monetary policy rules versus discretion debate the contribution of the geneva economists should be accorded a central place

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

a comparison of the ito and stratonovich formulations of problems in finance abstract a comparison of and the relationship between the ito and stratonovich formulations of stochastic integration is given it is argued that generally the ito formulation is appropriate for problems of finance and economics the black scholes option pricing problem is discussed in both frameworks with the ito formulation being shown to be clearly superior a finance example in which the stratonovich approach is simplest is also presented

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

entry and exit decisions based on a discount factor approach abstract entry and exit decisions under price uncertainty are discussed by a discount factor approach to investment the approach makes it possible to express the value of the firm as a function of a set of trigger prices at which investment takes place and to determine the optimal policy by simple maximization starting with a standard entry exit model by dixit 1989 entry and exit decisions under uncertainty journal of political economy 97 3 620 638 the paper expands to construction and scrapping decisions investment lags diminishing production capacity and limits to the number of lay up periods economic implications are investigated using experimental data and empirical shipping data

harvesting and recovery decisions under uncertainty abstract a stochastic forest rotation model in the faustmann tradition is presented and exemplified the model combines harvesting decisions with the potential to recover or clean up to restore the land after very unfavorable evolutions of the stochastic growth process uncertainty is shown to have a generally ambiguous effect on the optimal choice of investment strategy it is also shown how such models can be related to theory of optimal inventory control

reflections on food crises past abstract world food crises are relatively rare events occurring roughly three times a century but they also tend to be regular events every three decades or so suggesting there is an underlying cyclical cause if so far sighted donor and government investments in raising agricultural productivity and policies on behalf of stable food production and prices might go a long way to preventing food crises in the future preventing food crises rather than trying to cope after the fact with their impact on the poor is the only way to avoid substantial perhaps permanent damage to the welfare of poor households lessons from the world food crises in 1972 73 and in 2007 08 especially lessons from how the world rice market functioned point the way toward improved food policy management at national and international levels in the future

the dynamic behavior of efficient timber prices a simple theoreticalmodel of a tim consist ing of faustmann rotations evalubermarket finds that there exists a rational expecta ated at the mean of the price process tions equilibrium in which prices evolve according the central question addressed in this to a stationary a r 1 process simulations analyz e study is what is the appropriate model of a model with a more general representation of tim timber prices this is an important quesber stock dynamics implications for the optimal tion given the prescriptive nature of the harvesting literature are 1 market efficiency pro timber harvesting literature3 vides little justification for random walk prices 2 and evidence unit root tests used in previous studies to analyz e that the form of the price process strongly the informational efficiency of timber markets do influences the performance of a reservanot distinguish between efficient and inefficient tion price rule relative to the faustmann markets and 3 failure to recognize asymmetric rotation haight and holmes 1991 plandisturbances in time series analyses of historical tinga 1998 nonetheless most authors aptimber prices can lead to sub optimal harvesting pear to select the form of the price process rules

the effect of catastrophic risk on forest investment decisions abstract we analyze the effect of catastrophic risk on forest investment decisions by employing a forest level model where the output price is specified to follow a stochastic process we then incorporate a poisson jump process to reflect the occurrence of catastrophic events it is found that the presence of catastrophic risk always results in a reduced production value but an increased investment threshold for a forestry project however depending on the assumption regarding the option whether the right to invest can be maintained after the occurrence of such an event the degree and pattern of the effect are different

a real options approach to the valuation of a forestry investment abstract the theory of real options is used to model the optimal tree harvesting decision the value of the option to harvest is estimated using a dynamic programming approach and a general numerical solution technique suitable for any type of stochastic process for prices the conditions under which the optimal harvest time is independent of price are examined in addition the impact of assuming future lumber prices are mean reverting is considered it is found that option value and optimal cutting time are significantly different under the mean reversion assumption compared to geometric brownian motion

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