Ambiguity and uncertainty in Ellsberg and Shackle

This paper argues that Ellsberg’s and Shackle’s frameworks for discussing the limits of the (subjective) probabilistic approach to decision theory are not as different as they may appear. To stress the common elements in their theories Keynes’s Treatise on Probability provides an essential starting point. Keynes’s rejection of well-defined probability functions, and of maximisation as a guide to human conduct, is shown to imply a reconsideration of what probability theory can encompass, that is in the same vein of Ellsberg’s and Shackle’s concern in the years of the consolidation of Savage’s new probabilistic mainstream. The parallel between Keynes and the two decision theorists is drawn by means of a particular assessment of Shackle’s theory of decision, namely, it is interpreted in the light of Ellsberg’s doctoral dissertation. In this thesis, published only as late as 2001, Ellsberg developed the details and devised the philosophical background of his criticism of Savage as first put forward in the famed 1961 QJE article. The paper discusses the grounds on which the ambiguity surrounding the decision maker in Ellsberg’s urn experiment can be deemed analogous to the uncertainty faced by Shackle’s entrepreneur taking “unique decisions.” The paper argues also that the insights at the basis of the work of both Shackle and Ellsberg, as well as the criteria for decision under uncertainty they put forward, are relevant to understand the development of modern decision theory.uncertainty, weight of argument, non-additive probability

Cost Efficiency and Returns to Scope in Italian Investment Firms

This paper estimates cost efficiency and returns to scope of Italian investment firms during the period 1998-2002, following the stochastic frontier function approach. Results indicate a large inefficiency for Italian investment firms (with a high standard deviation across sample) and the absence of significant returns to scopeStochastic Frontier, Efficiency, Returns to scope, Investment Firms

The Avian Flu Disease: A Case of Precautionary Failure

The Precautionary Principle has been proposed as the proper behaviour to adopt in the face of the new catastrophic risks that have made their appearance in the last decades. We advance a workable definition of the Precautionary Principle and apply it to the possible outbreak among humans of the avian flu disease. We make use of a Principle-Agent model and show in which sense such outbreak can be considered a “Precautionary failure”.ambiguity, avian flu, precautionary principle, multiple priors

Deterrence and Compliance in a Demerit Point System

This paper attempts to outline the virtues and the perverse effects of a Demerit Point System (DPS). Under a DPS, once overcome a given threshold of demerit points, infringers are punished by severe non-monetary sanctions (such as the temporarily suspension of driving license in traffic enforcement). Surprisingly, no comprehensive economic theory has been provided to support the widespread implementation of DPS. This paper tries to fill this gap. We show that the impact of a DPS depends on the distribution of preferences of the population of potential infringers. For some agents a DPS far from increasing deterrence may actually reinforce deviant behavior. Only for some group of agents, once a given threshold of accumulated penalties has been reached compliance may occur. Thus compliance is obtained only after some level of under-deterrence is tolerated. We then provide some policy suggestions in order to improve general deterrence under a DPS for any given level of detection policy. Our results seem to be consistent with available evidence.Demerit Point System, Deterrence, Compliance, Recidivism, Public Law Enforcement, Traffic Law Enforcement

Diversity as Width

It is argued that if the population of options is a finite poset, diversity comparisons may be conveniently based on widths i.e. on the respective maximum numbers of pairwise incomparable options included in the relevant subposets. The width-ranking and the undominated width-ranking are introduced and characterized

Shackle versus Savage: non-probabilistic alternatives to subjective probability theory in the 1950s

G.L.S Shackle’s rejection of the probability tradition stemming from Knight's definition of uncertainty was a crucial episode in the development of modern decision theory. A set of methodological statements characterizing Shackle’s stance, abandoned for long, especially after Savage’s Foundations, have been re-discovered and are at the basis of current non-expected utility theories, in particular of the non-additive probability approach to decision making. This paper examines the discussion between Shackle and his critics in the 1950s. Drawing on Shackle’s papers housed at Cambridge University Library as well as on printed matter, we show that some critics correctly understood two aspects of Shackle’s theory which are of the utmost importance in our view: the non-additive character of the theory and the possibility of interpreting Shackle’s ascendancy functions as a specific distortion of the weighting function of the decision maker. It is argued that Shackle neither completely understood criticisms nor appropriately developed suggestions put forward by scholars like Kenneth Arrow, Ward Edwards, Nicholas Georgescu- Roegen. Had he succeeded in doing so, we contend, his theory might have been a more satisfactory alternative to Savage’s theory than it actually was.uncertainty, decision theory, non-additive measures

Quasi-option value under ambiguity

Real investments involving irreversibility and ambiguity embed a positive quasi-option value under ambiguity (q.o.v.a.), which modifies the evaluation of an investment decision involving depletion of natural resources by increasing the value of delaying. Q.o.v.a. depends on the specific decision-maker attitude towards ambiguity, expressed by a capacity on the state space. An empirical measure of q.o.v.a. is pointed out. Exploiting the properties of a capacity and its conjugate, the relationship has been established between the upper and lower Choquet integral with respect to a subadditive capacity and the bid and ask price of the underlying asset (output) of the investment decision. The empirical measure of q.o.v.a. is defined as the upper bound of the opportunity value. As an example, q.o.v.a. is applied to evaluate an off-shore petroleum lease under ambiguity.

Ambiguity and macroeconomics:a rationale for price stickiness

This paper deals with the emergence of price stickiness, that is nominal price elasticity below one, in the wake of nominal shocks. The setting of analysis is a general equilibrium model with both ambiguity and rational expectations. Ambiguity and macroeconomics are linked exploiting a micro-founded framework. Ambiguity concerns the lack of knowledge of firms about the relationship between changes in the aggregated stock of money and in the money distribution across heterogeneous consumers in the economy. Ambiguity is represented through a multiple priors approach. It is shown that price stickiness can emerge even if a change in the money supply level does not alter the distribution of money across consumers (uniform monetary policy). The key assumption made in the paper is that attitude towards ambiguity of firms is asymmetric: ambiguity aversion towards uncertain positive outcomes (gains) and ambiguity seeking towards negative outcomes (losses). By focusing on the dynamics of beliefs following a change in the stock of money that does not alter the money distribution, it is shown that money neutrality remains true in the long runAmbiguity, multiple priors, incomplete information, price stickiness

Production of a New Drug: A Sequential Investment ProcessUnder Uncertainty

On the basis of a database of more than 80 thousand records on total retails and production costs of the pharmaceutical industry worldwide we consider four classes of drugs. We evaluate the expected profits of an investment in a new drug in the four classes of pharmaceutical products by considering the standard NPV evaluation. We compare these outcomes with the evaluation of the expected profits of the four new drugs obtained by the real option approach. Interestingly enough quite different outcomes are obtained. These results loom on the capacity of standard methods to give a reliable evaluation of real investment projects that are analogous to compound optionscompound option, real option valuation, net present value, drugs

Contracts and Motivations. The Case of Open Source

The literature on Open Source phenomenon has revealed the crucial role played by both intrinsic and extrinsic motivations. However an analysis attempting to formally explore this interplay is still missing. In this paper, we try to fill the gap by introducing intrinsic motivations in standard principal-agent model, focusing on the case of Open Source Software (OSS). We show that, if developers’ intrinsic motivation is sufficiently high, paying developers to work on OSS projects allows the firm to induce a desired level of workers’ effort at a lower cost compared to the standard case of monetary incentives and sanctions coupled with costly monitoring.extrinsic and intrisic motivations, agency contracts, open-source software, open-source software developers