The public management of risk: Separating ex ante and ex post monitors

When a firm undertakes risky activities, the conflict between social and private incentives to implement safety care requires public intervention which can take the form of both monetary incentives and also ex ante or ex post monitoring, i.e., before or after an accident occurs. We delineate the optimal scope of monitoring depending on whether public monitors are benevolent or corruptible. We show that separating the ex ante and the ex post monitors increases the likelihood of ex post investigation, helps prevent capture and improves welfare.     

Unequal uncertainties and uncertain inequalities: an axiomatic approach

In this paper, we provide an axiomatic characterization of social welfare functions for uncertain incomes. Our most general result is that a small number of reasonable assumptions regarding welfare orderings under uncertainty rule out pure ex ante as well as pure ex post evaluations. Any social welfare function that satisfies these axioms should lie strictly between the ex ante and the ex post evaluations of income distributions. We also provide an axiomatic characterization of the weighted average of the minimum and the maximum of ex post and ex ante evaluations.     

Merger selection,evidence provision,and the timing of merger control

Merger control impacts the type of merger projects that are submitted, as well as the information provided by the merging parties upon assessment. In this paper, we consider the outcomes in terms of selection of merger types and evidence provision of alternative timings for merger review, pre- or postconsummation of the merger. We show that the selection effect induced by the ex post merger review is welfare-improving due to the deterrence of the most anticompetitive merger projects. In contrast, the welfare impact of evidence provision under ex post assessment is ambiguous. Balancing these two effects makes possible the welfare comparison between the ex ante and the ex post merger policy enforcement.     

Location decisions of a polluting firm and the time consistency of environmental policy

This paper considers location decisions of a monopolist, who faces a tax on its emissions in the home country, under ex post that is, time consistent, and ex ante, that is precommitment, environmental policies. We show that the monopolist will relocate more often under ex post optimal emission taxes. A government which cannot commit to an ex ante emission tax and sets its tax ex post after abatement effort has been chosen, is unable to affect the monopolist’s location decision, because it cannot commit to strategically reduce its tax level in the first stage. Domestic welfare is often higher under ex post emission taxes whenever the monopolist relocates under both policy regimes. Otherwise, welfare is higher under government commitment to an ex ante emission tax level. Thus, government commitment to a policy is not always welfare improving.     

On the efficiency of ex ante and ex post pricing institutions

Summary This paper compares the performance of three pricing institutions in a decentralized matching model in which random matching occurs. In the first, sellers make public ex ante commitments to trade at pre-specified prices before matching occurs. In the second, the buyer and seller engage in an alternating offer bargaining game once a match has occurred. In the final pricing institution, one party is chosen at random to make a take it or leave it price offer. The steady state equilibrium with ex ante pricing pareto dominates the steady state equilibrium with ex post take it or leave it offers, which in turn pareto dominates the steady state equilibrium with alternating offers. As the discount factor goes to one, the equilibrium with ex ante pricing generates participation rates that tend toward the pareto efficient level. The ex post pricing institutions generate participation rates that are bounded away from efficient levels. The surplus loss associated with switching from ex ante pricing to take it or leave it offers is small when the discount factor is close to one. Contrary to many models of decentralized trade, ex post pricing institutions encourage too much search by buyers.The financial support of the Social Sciences and Humanities Research Council of Canada is gratefully acknowledged. The research for this paper was completed while the author was visiting the University of California at San Diego. The author thanks Douglas Gale for comments.     

Ex ante and ex post long-run average cost functions

The traditional, neoclassical derivation of the long-run average cost(LAC) function is based on minimizing the cost of a given output. However, there are a number of reasons why the theoretical concept of this ex ante LAC function is likely to differ significantly from ex post cost-output observations when output is stochastic. In agriculture, the farmer's decision making criterion is assumed to be one of minimizing the cost of producing some planned output level. Average cost is then a function, inter alia, of planned output rather than realized output. It is argued that there is no operational significance in the cost-realized output relationship; in practice, the farmer's concern is with the cost-planned output relationship. This paper proposes a two-stage procedure to estimate the latter relationship. Cross-section data on UK dairy farms for 1980/1 are used to show significant differences in the ex ante and ex post relationships.     

Is ex‐ante ex‐post analysis irrelevant to Keynes's theory of employment?

Ex‐ante ex‐post analysis has become a standard tool in macroeconomics. Yet Keynes dismissed it. We argue that Keynes's dismissal of ex‐ante ex‐post analysis is not an oddity but an indication of the originality of his theory of employment compared to standard macroeconomics. First, the principle of effective demand does not amount to a process that determines employment and income at the point of intersection of the traditionally defined ex ante supply and demand functions. Second, the finance motive allowed Keynes to confirm the identity of aggregate supply and demand already asserted in The General Theory. This latter conclusion is puzzling, however, since the principle of effective demand presupposes the possibility of a discrepancy between supply and demand. We suggest that Keynes's theory of employment is linked to a theory of income distribution whereby profits are a redistributed share of factor income which is transferred to firms when prices exceed factor costs. The identity and the equilibrium condition then relate to separate measurements of income and output, factor cost and prices.     

The Analysis of Professional Sports Leagues as Joint Ventures

This paper addresses whether the welfare analysis of the agreements and rules of a professional sports league should depend on the organisational form chosen by the league's participants. Courts have analysed sports leagues both as associations of horizontal competitors and as single entities. The former approach suggests much less tolerance for rules that affect competition. Drawing on the distinction between ex ante and ex post competition that has been found useful in the economic analysis of intellectual property rights, the authors suggest a middle road in the horizontal competitors versus single entity characterisations of professional sports leagues.     

Welfare economics,risk and uncertainty

Social decisions in risky contexts raise a number of difficult questions, such as: (1) Should social decisions be more or less risk averse than the average person? (2) Should we try to avoid large catastrophes more than frequent but limited harms with similar expected impact? (3) Should social decisions be ambiguity averse or stick to the expected utility canon? This paper reviews the welfare economics of risk and uncertainty and examines possible answers to these questions, based on the pros and cons of utilitarianism, ex ante egalitarianism and ex post egalitarianism.     

Increasing consumer well-being: risk as potential driver of happiness

This article investigates the relation between risk and individual well-being. We propose a theoretical model of happiness that makes a distinction between ex ante evaluations of happiness and ex post assessments. The main assumptions of the model are tested through three studies based on anchoring vignettes. We show that, even if, ex ante, consumers fear high risk and do not associate it to a high level of happiness, their ex post evaluation of well-being is generally higher when identical consequences result from a high-risk situation than from a low-risk situation. Control over risk-taking reinforces the gap between ex ante and ex post measures of happiness. Thus, our article provides empirical evidence about a positive relation between risk and individual well-being, suggesting that risky experiences have the potential to increase consumer well-being.     

Ex ante valuation of atmospheric visibility

In a world incomplete markets for environmental goods, ex ante planned expenditures rather than ex post realized outcomes explain the values which individuals attach to these goods. We use the distance function to develop restrictions from a model of ex ante consumer behaviour involving these goods. A Contigent valuation approach is then employed to estimate policy-relavant components of the ex ante economic values that recreationists attach to differing subjective probabilities of alternative atmospheric visibility levels at a wilderness location and at an urban location in Oregon. Marginal valuations of probability changes are similar at the two sites. Marginal rates of time preference for resolving uncertainities vary between 10 and 50% and are inversely related to education. Existence value averages 10% of total value, and evidence is mixed that site-specific value act as surrogates for general environmental preferences.     

从事前效率问题到事后效率问题——不完全合同理论的几类经典模型比较

通过对不完全合同经典理论模型的组成要素的梳理和分类,本文首次将不完全合同理论的模型分为四种类型:行动事前不可缔约而事后可缔约的事前效率问题模型,行动事前和事后都不可缔约的事前和事后效率问题模型,事前部分可缔约的事前和事后效率问题模型,收益事后不可证实的事前和事后效率问题模型。这些不同的理论被纳入一个统一的框架中进行表述。传统的产权理论具有一些缺陷,而事后不可缔约的模型更适合研究权威、授权、科层等问题。相对于关于投资激励的事前效率问题,事后效率问题的来源要多得多。对事前与事后缔约性问题的探讨以及对事后效率问题的研究是丰富不完全合同理论发展的动力。     

Welfare-optimal pricing and capacity selection under an ex ante maximum demand charge

This paper deals with the simultaneous determination of welfare-optimal pricing and investment rules under a multi-period ex ante maximum demand charge by allowing the possibility of purchasing electricity from third party generators at some cost when excess demand occurs. I show that at the optimal size of capacity, expected short-run marginal shortage cost and long-run marginal capacity cost should be equal. The optimal maximum demand tariff does not entail marginal cost pricing. In general, it is shown that maximum demand charges are welfare superior to marginal cost pricing when tariffs must be set ex ante, before demand is known.     

EX POST VERSUS EX ANTE MEASURES OF THE USER COST OF CAPITAL

Should we use ex post or ex ante measures of user costs to calculate the contribution of capital in a growth accounting exercise? The answer, based on a simple model of temporary equilibrium, is that ex post is better in theory. In practice researchers usually calculate ex post user costs by assuming that the rate of return is equalized across assets. But this is only true if expectations are correct. In general, the ex post rate of return differs between assets, even though ex ante it is the same. I propose a hybrid method. The index of capital services is estimated using ex ante weights; the contribution of capital is the growth of this index multiplied by the ex post income share of capital. I show that this method is theoretically correct if the production function is CES. I compare the ex post, ex ante and hybrid methods using data for 31 U.K. industries from 1970 to 2000.     

Sharing oil rents and political violence

This paper investigates how the devolution of oil windfalls affects the likelihood of political violence. It shows that transferring large shares of oil wealth can prevent conflict, while transferring small shares can trigger it. Among the different transfer schemes, fiscal transfers (to subnational governments) yield the highest levels of consumption, but direct transfers (to people) are the most effective in preventing conflict. By averting conflict, transfers can improve ex ante welfare; however, only a subset of the ex ante welfare optimal transfers is optimal ex post and thus self-enforcing. Among them, those that avert conflict by reinforcing repressive regimes are of particular policy interest.     

Policy Discrimination with and without Interpersonal Comparisons of Utility

Can the Pareto criterion guide policymakers who do not know the true model of the economy? If policymakers specify ex ante preferences for agents, then Pareto improvements from a distorted status quo are usually possible, and with more commodities than states, one can implement almost every Pareto optimum. Unlike the standard second welfare theorem, planners cannot dictate allocations: agents must trade. Unfortunately ex ante preferences impose interpersonal comparisons. If policymakers merely aim to maximize some social welfare function then optimal policies form an open set; hence small changes in the environment do not necessitate any policy response. Planners with symmetric information about agents can sometimes intervene without making interpersonal comparisons.     

Regionalism and the Rest of the World: Theory and Estimates of the Effects of European Integration

There are no satisfactory ex post estimates of the effects of regional integration on excluded countries' welfare. Using a formal decomposition of welfare, this paper discusses the factors that might affect these countries' welfare and aspects of their measurement. It then surveys various ex ante estimates of the effects of European integration. These suggest that neighboring countries linked tightly to the European economy could lose significantly from the latter's integration, but that for other countries the losses are likely to be very small.     

Frontrunners and Laggards: The Strategy of Environmental Regulation under Uncertainty

The extant literature on the political economy of environmental regulation does not provide a unified theoretical explanation for three salient stylized facts. First, companies voluntarily invest to reduce the environmental burden that they cause under threat of regulation. Second, ex ante estimates of the compliance cost tend to be systematically higher than ex post estimates. Finally, regulators use limited information provided by the industry. I construct a game-theoretic model of environmental regulation under uncertainty with a benevolent regulator. In equilibrium, companies undertake voluntary action to induce regulation that raises barriers to entry. This profit-driven behavior is not always socially detrimental, however, as the regulator obtains a credible commitment to production and a more accurate estimate of the compliance cost. Additionally, the results provide a selection explanation for the mismatch between ex ante and ex post cost estimates: if companies condition compliance on the installation cost, only low-cost companies install in equilibrium. The analysis combines “regulatory capture” with social welfare maximization to explain the curious combination of voluntary action and low ex post compliance cost without serious information collection by the regulator.     

Social security and risk sharing

In this paper we identify conditions under which the introduction of a pay-as-you-go social security system is ex ante Pareto-improving in a stochastic OLG economy with capital accumulation and land. We argue that these conditions are consistent with realistic specifications of the parameters of the economy. In our model financial markets are complete and competitive equilibria interim Pareto efficient. Therefore, a welfare improvement can only be obtained if agents? welfare is evaluated ex ante, and arises from an improvement in intergenerational risk sharing. We also examine the optimal size of a given social security system as well as its optimal reform.     

Payoff equivalence between Bayesian and ex post individually rational dominant strategy mechanisms

Summary. An efficient, interim individually rational, ex post budget balanced Bayesian mechanism is shown to be payoff equivalent to an ex post individually rational and ex ante budget balanced dominant strategy mechanism. This result simplifies the search for mechanisms that implement efficient allocation rules by pointing to a class of Groves mechanisms. It eliminates the strict requirement of common knowledge of priors and can be applied to many problems of incomplete information. Received: October 22 1996; revised version: November 25, 1997