Polarization,Political Instability and Active Learning*

In a multiperiod setting, decision‐makers can learn about the consequences of their decisions through experimentation. We examine how polarization and political instability affect learning through experimentation. We distinguish two cases: (i) the decision to be made is not salient and does not affect the outcome of subsequent elections (exogenous elections) and (ii) the decision is salient and the election outcome depends on it (endogenous elections). It is shown that while the possibility of learning increases activism, the existence of political instability distorts learning. Furthermore, we demonstrate that, when elections are exogenous, polarization between political parties does not always decrease active learning.     

New product launch: herd seeking or herd preventing?

A decision maker offers a new product to a number of potential adopers. He does not know the value of the product, but adopers receive some private information about it. We study how the decision maker may influence learning among adopers by manipulaing the launch sequence when both the decision maker and adopers can learn about the value of the product from previous adoption decisions. The conditions under which the decision maker prefers a sequential launch to a simultaneous launch depend on adopers?? prior beliefs about the value of the product and adoption costs. We derive the decision maker??s optimal launch sequence and study how it endogenizes informational herding.     

Taxes versus quotas for a stock pollutant

We compare the effects of taxes and quotas for an environmental problem where the regulator and polluter have asymmetric information about abatement costs, and environmental damage depends on pollution stock. An increase in the slope of the marginal abatement cost curve, or a decrease in the slope of the marginal damage curve, favors taxes. An increase in the discount rate or the stock decay rate favors tax usage. Taxes dominate quotas if the length of a period during which decisions are constant is sufficiently small. An empirical illustration suggests that taxes dominate quotas for the control of greenhouse gasses.     

Optimal control of an invasive species with imperfect information about the level of infestation

The presence of invasive species is often not realized until well after the species becomes established. Discovering the location and extent of infestation before the invasive species causes widespread damage typically requires intensive monitoring efforts. In this paper, we analyze the problem of controlling an invasive species when there is imperfect information about the degree of infestation. We model the problem as a partially observable Markov decision process in which the decision-maker receives an imperfect signal about the level of infestation. The decision-maker then chooses a management action to minimize expected costs based on beliefs about the level of infestation. We apply this model to a simple application with three possible levels of infestation where the decision-maker can choose to take no action, only monitor, only treat, or do both monitoring and treatment jointly. We solve for optimal management as a function of beliefs about the level of infestation. For a case with positive monitoring and treatment costs, we find that the optimal policy involves choosing no action when there is a sufficiently large probability of no infestation, monitoring alone with intermediate probability values and treatment alone when the probability of moderate or high infestation is large. We also show how optimal management and expected costs change as the cost or quality of information from monitoring changes. With costless and perfect monitoring, expected costs are 20–30% lower across the range of belief states relative to the expected costs without monitoring.     

Integrating dynamic pricing and inventory control for fresh‐agri product under consumer choice

In this article, we investigate a joint pricing and inventory problem for a retailer selling fresh‐agri products (FAPs) with two‐period shelf lifetime in a dynamic stochastic setting, where new and old FAPs are on sale simultaneously. At the beginning of each period, the retailer makes ordering decision for new FAP and sets regular and discount prices for new and old inventories, respectively. After demand realisation, the expired leftover is disposed and unexpired inventory is carried to the next period, for continuing selling. Unmet demand of all FAPs is backordered. The objective is to maximise the total expected discount profit over the whole planning horizon. We present a price dependent, stochastic dynamic programming model taking into account zero lead‐time, linear ordering costs, inventory holding and backlogging costs, as well as disposal cost. As the influence of the perishability, each customer selects his preferred choice based on the utility of product price and quality. By the way of constructing demand rate vector, the original formulation can be transferred to be jointly concave and tractable. Finally, we characterise the optimal policy and develop effective methods to solve the problem. We also conduct numerical studies to further characterise the optimal policy, and to evaluate the loss of efficiency under static policies when compared to the optimal dynamic policy.     

Time and uncertainty in resource dilemmas: equilibrium solutions and experimental results

Most common pool resource (CPR) dilemmas share two features: they evolve over time and they are managed under environmental uncertainties. We propose a stylized dynamic model that integrates these two dimensions. A distinguishing feature of our model is that the duration of the game is determined endogenously by the users’ collective decisions. In the proposed model, if the resource stock level below which the irreversible event occurs is known in advance, then the optimal resource use coincides with a unique symmetric equilibrium that guarantees survival of the resource. As the uncertainty about the threshold level increases, resource use increases if users adopt decision strategies that quickly deplete the resource stock, but decreases if they adopt path strategies guaranteeing that the unknown threshold level is never exceeded. We show that under relatively high uncertainty about resource size, CPR users frequently implement decision strategies that terminate the game immediately. When this uncertainty is reduced, they maintain a positive resource level for longer durations.     

Harvest and extinction in multi-species ecosystems

A potential cost of harvesting in multi-species ecosystems is the extinction of nonharvested species that are at the same trophic level as the harvested species. Existing analytical models are not well-suited for studying this harvest externality because they focus on species interactions across trophic levels instead of within them. We identify the conditions under which the harvesting of a single species causes at least one extinction of nonharvested species at the same trophic level. We compare two harvest regimes: uniform management, in which a privately optimal harvest rate is applied to the entire ecosystem; and specialized management, in which a portion of the ecosystem is intensively managed for the harvested species and the rest is left unharvested. Which regime is more likely to result in extinction depends on the discount rate and on the harvested species' competitive ability and colonization rate compared to those of the other species.     

Regulatory tune-ups

Regulators cannot continuously and perfectly monitor firms. The alternative considered here supposes the regulator sets prices at discrete, unforeseen, times. I show that when marginal cost follows a stochastic diffusion process, but the regulator only irregularly adjusts the regulated price, the optimal price may be less than or greater than the expected level of marginal costs. The regulated price should be higher the steeper the demand curve, the lower the discount rate, and the greater the variance of costs. The social benefit of changing the price following a change in marginal cost is usually greater if at the time price was set marginal cost was low.     

Cost-benefit analysis of alien vegetation clearing for water yield and tourism in a mountain catchment in the Western Cape of South Africa

Economic analysis is used to assess the costs and benefits of restoration following clearing of invasive alien trees in the floristically rich Fynbos mountainous area near Franschhoek, Western Cape of South Africa. The Groot Drakenstein, Franschhoek and Jonkershoek mountains receives more rainfall than the surrounding areas and is an important source of water for the city of Cape Town. The costs of alien invasive plant removal, gully-erosion repair and reseeding with indigenous plants are considered in a case-study cost-benefit analysis of restoration, in terms of the water and tourism benefits derived. Three different options of restoration (comprehensive, moderate, basic) were analysed under three different economic scenarios (optimistic, realistic, pessimistic) and the costs of which have been weighted up against the income derived from the supply of water and tourism. The results have shown that despite the high costs of restoration, the basic restoration option costs were out-weighed by the water and tourism benefits derived. This was also true of the moderate restoration option, when evaluated under the optimistic scenario and using an 8% discount rate, or a 3% discount rate under any scenario. However, this was not the case in the moderate restoration option when using an 8% discount rate in conjunction with the realistic and pessimistic scenarios. Neither was it the case when using a 12% discount rate, irrespective of the scenario. Under no scenario was the cost of a comprehensive restoration option outweighed by the benefits quantified, irrespective of the discount rate used. It was concluded that further restoration, in addition to the mere clearing of alien invasive plants, would be economically viable under certain assumptions and conditions.     

Optimal Worksharing Discounts

Forty percent of first-class mail is workshared, meaning that mailers perform part of the postal service work, such as sorting, in exchange for a price discount. Here the optimal discount is shown to depend on whether mailers workshare all their mail. If they do, their marginal decisions will affect usage of the mail, and the normal Ramsey inverse-elasticity rule will apply. If they do not, and their marginal decision involves the amount of their worksharing, then worksharing supply elasticities play a role in the optimal discount. In the latter case, margins will be greater for workshared letters. Problems in balancing these solutions, and in estimating cost savings from worksharing, are also discussed.     

Demand uncertainty and the value of supply opportunities

The study considers the optimal timing of production decisions under demand uncertainty. In accordance with the modern theory of irreversible investment, the problem is modelled as one of optimal stopping. By taking an approach which is independent of dynamic programming and the smooth-fit principle, we derive explicitly both the value of the opportunity and the optimal-demand threshold. We prove that the optimal-demand threshold can be attained at a point where the smooth-fit principle is not valid. We also carry out the comparative static analysis of the optimal variables and derive conditions under which production incentives are held constant. A consequence of this analysis is that along the iso-incentive curve inflationary policy must be counteracted with strict monetary policy.     

Restoring Wetlands Through Wetlands Mitigation Banks

This paper offers the first economic analysis of wetlands mitigation banks. The banks are a new alternative for restoration of wetlands by developers before receiving regulatory approval for future development of wetlands in the same watershed. A stochastic optimal control model is developed which incorporates ecological uncertainty of wetlands restoration. The model helps in examining the decisions of how much to invest in a wetlands mitigation bank. The model is calibrated with data from California bioeconomic parameters. Numerical simulation of the model provides a sensitivity analysis of how model parameters of restoration costs, stochastic biological growth, interest rate, and the market value of credits affect the trajectory of investment and the optimal stopping state of wetlands quality when the investment ends. The analysis reveals that restoration of the whole site will occur when there is a reduction in restoration costs, an increase in biological uncertainty or an increase in the value of wetlands credits. Continued restoration is harder to justify with a higher interest rate.     

Irreversibilities and the timing of environmental policy

The standard framework in which economists evaluate environmental policies is cost–benefit analysis, so policy debates usually focus on the expected flows of costs and benefits, or on the choice of discount rate. But this can be misleading when there is uncertainty over future outcomes, when there are irreversibilities, and when policy adoption can be delayed. This paper shows how two kinds of uncertainty — over the future costs and benefits of reduced environmental degradation, and over the evolution of an ecosystem — interact with two kinds of irreversibilities — sunk costs associated with an environmental regulation, and sunk benefits of avoided environmental degradation — to affect optimal policy timing and design.     

Optimal Experimentation in a Changing Environment

This paper studies optimal experimentation by a monopolist who faces an unknown demand curve subject to random changes, and who maximizes profits over an infinite horizon in continuous time. We show that there are two qualitatively very different regimes, determined by the discount rate and the intensities of demand curve switching, and the dependence of the optimal policy on these parameters is discontinuous. One regime is characterized by extreme experimentation and good tracking of the prevailing demand curve, the other by moderate experimentation and poor tracking. Moreover, in the latter regime the agent eventually becomes "trapped" into taking actions in a strict subset of the feasible set.     

Parental expectations and school enrolment decisions: Evidence from rural Ghana

We use field data to investigate factors that influence parents' decisions to enrol children in schools in rural Ghana. The empirical results identified a host of socio‐economic and household‐level factors including remittances parents expect from investing in education, parents perception of a child's desirable professions, cost of schooling and discount rate as significant determinants of parental school enrolment decision. When gender of the child and remittances are taken into account, we show male parents are more likely to invest in education of boys than girls because they expect significantly higher returns from their investment in boys. Female parents do not show such gender preference. The proportion of children enrolled in school is positively related to average cost of schooling for male parents Gender of parent plays a significant role in school enrolment decision making.     

Ecological discounting

Which rates should we use to discount costs and benefits of different natures at different time horizons? We answer this question by considering a representative agent consuming two goods whose availability evolves over time in a stochastic way. We extend the Ramsey rule by taking into account the degree of substitutability between the two goods and of the uncertainty surrounding the economic and environmental growths. The rate at which environmental impacts should be discounted is in general different from the one at which monetary benefits should be discounted. We provide arguments in favor of an ecological discount rate smaller than the economic discount rate. In particular, we show that, under certainty and Cobb-Douglas preferences, the difference between the economic and the ecological discount rates equals the difference between the economic and the ecological growth rates. Using data about the link between biodiversity and economic development, I estimate that the rate at which changes in biodiversity should be discounted is 1.5%, whereas changes in consumption should be discounted at 3.2%.     

Social Discount Rates from Stratospheric Ozone Control*

We develop a model of optimal project timing to infer the discount rate US residents attach to investments in stratospheric ozone preservation. In this model, the calendar date at which preservation-related benefits offset costs is shown to be an increasing function of the real social rate of time preference. Estimates of US costs and benefits associated with the original (1987) Montreal Protocol are used to determine a range of discount rates from the US control of stratospheric ozone depletion. From this example the range is about 3.0 to 8.77 per cent.     

Learning about the arrival of sales

We analyse optimal stopping when the economic environment changes because of learning. A primary application is optimal selling of an asset when demand is uncertain. The seller learns about the arrival rate of buyers. As time passes without a sale, the seller becomes more pessimistic about the arrival rate. When the arrival of buyers is not observed, the rate at which the seller revises her beliefs is affected by the price she sets. Learning leads to a higher posted price by the seller. When the seller does observe the arrival of buyers, she sets an even higher price.     

Trade Policy in the Presence of Technology Licensing*

We consider strategic trade policy when a high‐cost and a low‐cost firm belonging to two different countries compete in quantities in a third country, and technology is transferable via licensing. We characterize the effects of subsidies on (i) licensing payments—a new source of rents, (ii) the decision to license, and (iii) the subsidy bill difference (compared to when licensing is infeasible). We find that, in the presence of licensing, optimal strategic trade policy has several interesting features. For example, even under Cournot competition, optimal policy can be an export tax instead of an export subsidy. Also, unlike results in strategic trade policy with asymmetric costs, we find that optimal export subsidies are not necessarily positively related to the cost‐competitiveness of firms. In other words, governments need not necessarily favor “winners” when licensing is possible. Furthermore, there exist parameterizations such that a government, if it can, might ban licensing.     

Optimal Pricing and Price-Cap Regulation in the Postal Sector

This paper studies the optimal price structure in the postal sector when worksharing is available (e.g., for collection, sorting and transportation) and when the operator faces a break-even constraint. Users differ in opportunity and cost to engage in worksharing. We determine the optimal worksharing discount and provide sufficient conditions (on demand functions) under which it exceeds the ECPR level. Furthermore, we show that the optimal prices can be implemented through a global price cap imposed on a weighted average of the prices of all products. The appropriate weights are proportional to the market demand (evaluated at optimal prices) of the corresponding products.