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on Utility Models and Prospect Theory |
| By: | Kontek, Krzysztof |
| Abstract: | Prospect Theory (1979) and its Cumulative version (1992) argue for probability weighting to explain lottery choices. Decision Utility Theory presents an alternative solution, which makes no use of this concept. The new theory distinguishes decision and perception utility, postulates a double S-shaped decision utility curve similar to one hypothesized by Markowitz (1952), and applies the expected decision utility value similarly to the theory by von Neumann and Morgenstern (1944). Decision Utility Theory proposes straightforward risk measures, presents a simple explanation of risk attitudes by using the aspiration level concept, and predicts that people might not consider probabilities and outcomes jointly, on the contrary to the expected utility paradigm. |
| Keywords: | Expected Utility Theory; Markowitz Hypothesis; Prospect Theory; Decision Utility; Allais Paradox; Common Ratio Effect; Risk Attitude Measures; Aspiration Level. |
| JEL: | D81 C91 |
| Date: | 2010–12–01 |
| URL: | http://d.repec.org/n?u=RePEc:pra:mprapa:27141&r=upt |
| By: | Fabio Maccheroni; Massimo Marinacci; Doriana Ruffino |
| Abstract: | We derive the analogue of the classic Arrow-Pratt approximation of the certainty equivalent under model uncertainty as de ned by the smooth model of decision making under ambiguity of Klibano¤, Marinacci and Mukerji (2005). We study its scope via a portfolio allocation exercise that delivers a tractable mean-variance model adjusted for model uncertainty. In a problem with a risk-free asset, a risky asset, and an ambiguous asset, we nd that portfolio rebalancing in response to higher model uncertainty only depends on the ambiguous assets alpha, setting the performance of the risky asset as benchmark. In addition, the portfolios recommended by our model are not systematically conservative on the share held in the ambiguous asset: indeed, in general, it is not true that greater ambiguity reduces the optimal demand for the ambiguous asset. The analytical tractability of the enhanced Arrow-Pratt approximation renders our model especially well suited for calibration exercises aimed at exploring the consequences of ambiguity aversion on equilibrium asset prices. |
| Date: | 2010 |
| URL: | http://d.repec.org/n?u=RePEc:igi:igierp:373&r=upt |
| By: | Martin J Osborne; Rabee Tourky |
| Date: | 2010–12–09 |
| URL: | http://d.repec.org/n?u=RePEc:cla:levarc:506439000000000050&r=upt |
| By: | Berg, Nathan; Gigerenzer, Gerd |
| Abstract: | For a research program that counts improved empirical realism among its primary goals, it is surprising that behavioral economics appears indistinguishable from neoclassical economics in its reliance on “as-if” arguments. “As-if” arguments are frequently put forward in behavioral economics to justify “psychological” models that add new parameters to fit decision outcome data rather than specifying more realistic or empirically supported psychological processes that genuinely explain these data. Another striking similarity is that both behavioral and neoclassical research programs refer to a common set of axiomatic norms without subjecting them to empirical investigation. Notably missing is investigation of whether people who deviate from axiomatic rationality face economically significant losses. Despite producing prolific documentation of deviations from neoclassical norms, behavioral economics has produced almost no evidence that deviations are correlated with lower earnings, lower happiness, impaired health, inaccurate beliefs, or shorter lives. We argue for an alternative non-axiomatic approach to normative analysis focused on veridical descriptions of decision process and a matching principle – between behavioral strategies and the environments in which they are used – referred to as ecological rationality. To make behavioral economics, or psychology and economics, a more rigorously empirical science will require less effort spent extending “as-if” utility theory to account for biases and deviations, and substantially more careful observation of successful decision makers in their respective domains. |
| Keywords: | bounded rationality; ecological rationality; as-if; fit; prediction; decision; process |
| JEL: | B1 B4 |
| Date: | 2010 |
| URL: | http://d.repec.org/n?u=RePEc:pra:mprapa:26586&r=upt |
| By: | Pascal François; Georges Hübner |
| Abstract: | This paper studies the contracting choices between an entrepreneur and venture capital investors in a portfolio context. We rely on the mean-variance framework and derive the optimal choices for an entrepreneur with and without the presence of different kinds of venture capitalists. In particular, we show that the entrepreneur always has the incentive to share the risk and benefits of the venture whenever possible. On the basis of their objectives and characteristics, we distinguish the situations of the corporate, independent, and bank-sponsored venture capital funds. Our framework enables us to derive the optimal contract design for the entrepreneur, featuring the choice of investor, the entrepreneur’s investment in the venture, and her dilution in the project’s equity as a function of her bargaining power. This result allows us to characterize the choice of the investor depending on her cost of equity and debt capital. In addition to project size and risk, entrepreneur’s risk aversion turns out to be a critical determinant of VC investor choice –a finding which is strongly supported by a panel analysis of VC fund flows for 5 European countries over the 2002-2009 period. |
| Keywords: | Venture capital, Portfolio choice, Entrepreneur, Risk aversion |
| JEL: | G11 G32 G39 |
| Date: | 2010 |
| URL: | http://d.repec.org/n?u=RePEc:lvl:lacicr:1046&r=upt |
| By: | Narayana Kocherlakota |
| Date: | 2010–12–08 |
| URL: | http://d.repec.org/n?u=RePEc:cla:levarc:2053&r=upt |
| By: | Guillaume Hollard (CES - Centre d'économie de la Sorbonne - CNRS : UMR8174 - Université Panthéon-Sorbonne - Paris I, EEP-PSE - Ecole d'Économie de Paris - Paris School of Economics - Ecole d'Économie de Paris); Sébastien Massoni (CES - Centre d'économie de la Sorbonne - CNRS : UMR8174 - Université Panthéon-Sorbonne - Paris I); Jean-Christophe Vergnaud (CES - Centre d'économie de la Sorbonne - CNRS : UMR8174 - Université Panthéon-Sorbonne - Paris I) |
| Abstract: | Since they have been increasingly used in economics, elicitation rules for subjective beliefs are under scrutiny. In this paper, we propose an experimental design to compare the performance of such rules. Contrary to previous works in which elicited beliefs are compared to an objective benchmark, we consider a pure subjective belief framework (confidence in own performance in a cognitive task and a perceptual task). The performances of elicitation rules are assessed according to the accuracy of stated beliefs in predicting success. For the perceptual task we also compare stated beliefs to Signal Detection Theory predictions. We find consistent evidence in favor of the Lottery Rule which provides more accurate beliefs and is not sensitive to risk aversion. Furthermore the Free Rule, a simple rule with no incentives, elicits relevant beliefs and even outperforms the Quadratic Scoring Rule. Beside this comparison, we propose a belief formation model where we distinguish between two stages in the beliefs : beliefs for decision making and confidence beliefs. Our results give support to this model. |
| Keywords: | Belief elicitation, confidence, Signal Detection Theory, methodology, incentives, experimental economics. |
| Date: | 2010–11 |
| URL: | http://d.repec.org/n?u=RePEc:hal:cesptp:halshs-00543828_v1&r=upt |
| By: | Berg, Nathan |
| Abstract: | This article describes the emerging subfield known as behavioral economics, which borrows from psychology, empirically tests assumptions used elsewhere in economics, and provides theories that aim to be more realistic and closely tied to experimental and field data. Highlights from the experimental findings of behavioral economics are discussed. The article remarks critically on the role of empirical realism and continued use of as-if methodology in behavioral economics. Problems in normative behavioral economics are given special attention as debates arise concerning how to interpret empirical findings that contradict standard definitions of axiomatic rationality. Ecological rationality, methodological pluralism, and Simon's notion of bounded rationality are considered. |
| Keywords: | bounded rationality; ecological rationality; Herbert Simon; as-if; survey |
| Date: | 2010 |
| URL: | http://d.repec.org/n?u=RePEc:pra:mprapa:26587&r=upt |
| By: | Liégeois P; Islam N |
| Abstract: | In discrete choice labour supply analysis, it is often reasonably expected that utility is increasing with income. Yet, analyses based on discrete choice models sometimes mention that, when no restriction is imposed a priori in the statistical optimization program, the monotonicity condition is not fully satisfied ex post. Obviously, the standard statistical optimization program might be completed with conditions (one per individual) imposing positive marginal utilities. Unfortunately, such a high-dimensional program most often appears to be rather time-consuming in order to be solved, if not practically unsolvable. In order to overcome this drawback, some authors impose general parametric restrictions a priori (hence reducing de facto the dimension of the parameter set), which is sufficient to lead to positive marginal utilities ex post. However, those restrictions might sometimes appear to be unnecessarily too severe and then generate a sub-optimal set of estimated values for the parameters of the utility function. Alternatively, we show that it may be easy to avoid unnecessary restrictions. The high-dimensional program including conditions for positive marginal utilities for all can sometimes be equivalently replaced by a one-dimensional one. At the end, no observation is hopefully showing negative marginal utility anymore at optimum. |
| JEL: | C25 C61 H31 J22 |
| Date: | 2010–11–23 |
| URL: | http://d.repec.org/n?u=RePEc:ese:emodwp:em6/10&r=upt |