How choice proliferation affects revealed preferences

Theory and Decision - Whereas the literature on choice overload has shown that people tend to defer their choice or experience less satisfaction under choice proliferation, this paper aims to test...     

Does Privatization Protect Natural Resources? Property Rights and Forests in Guatemala

Objectives . Property rights are central to debates about natural resource policy. Governments traditionally have been seen as the appropriate custodians of natural resources for their citizens. More recently, many argue the privatization of property rights will ensure that users have incentives to manage their resources well. Common property, to the extent it is discussed at all, is seen as leading to the tragedy of the commons. We evaluate these claims by assessing property rights and forest conditions in two private and three communal forests in Guatemala. Methods . Data on biological and social phenomena from five forests (151 plots) and their associated communities were collected using the International Forestry Resources and Institutions Research Program protocols. Ordinary least squares regression was used to analyze four models. We examined t -scores for differences in coefficients for the different models. Results . The models demonstrate that de jure property rights are not a powerful predictor of variations among the sampled forests. Conclusions . We argue that de facto institutions and their enforcement are much more important than de jure property rights to forest management. Communities holding a forest in common can, under certain circumstances, create institutions to manage their resources as successfully as—or more successfully than—private owners.     

Tools for decision making under imprecise risk

Generalizing risk, imprecise risk is a situation where available objective information is expressible by a lower probability. We study properties of certain lower probabilities in metrizable spaces. Necessary and sufficient conditions are derived for stability of their cores under image and mixture, which are useful features in applying Expected Utility Theory under imprecise risk. Received: December 2000; revised version: March 2001     

Maximum entropy estimation for survey sampling

Calibration methods have been widely studied in survey sampling over the last decades. Viewing calibration as an inverse problem, we extend the calibration technique by using a maximum entropy method. Finding the optimal weights is achieved by considering random weights and looking for a discrete distribution which maximizes an entropy under the calibration constraint. This method points a new frame for the computation of such estimates and the investigation of its statistical properties.     

Tribute to Jean-Yves Jaffray

Tribute to Jean-Yves Jaffray by the French Group of Decision Theory.     

Questions of process in participant-generated visual methodologies

There is an increasing literature on visual methodologies in which images are generated by participants as part of the research, as distinct from the analysis of existing images or images taken by the researcher. Although there are growing numbers of publications that present frameworks for analysing images and their meaning, this is an area requiring further deliberation and consolidation. Our contribution is to give serious attention to the processes of image production in participant-generated visual methodologies. We examine methodological and ethical considerations that arise before, during and after image production. Our work is in health research and we focus specifically on two methods: first, a combination of photovoice and photo-elicitation, in particular with young people; and second, drawings as research method. Based on examples using these two methods, we pose questions of process for image production and submit this for interrogation for reasons of methodological, analytical and ethical rigour.     

Condorcet efficiency: A preference for indifference

The Condorcet winner in an election is the candidate who would be able to defeat all other candidates in a series of pairwise elections. The Condorcet efficiency of a voting procedure is the conditional probability that it will elect the Condorcet winner, given that a Condorcet winner exists. The study considers the Condorcet efficiency of weighted scoring rules (WSR's) on three candidates for large electorates when voter indifference between candidates is allowed. It is shown that increasing the proportion of voters who have partial indifference will increase the probability that a Condorcet winner exists, and will also increase the Condorcet efficiency of all WSR's. The same observation is observed when the proportion of voters with complete preferences on candidates is reduced. Borda Rule is shown to be the WSR with maximum Condorcet efficiency over a broad range of assumptions related to voter preferences. The result of forcing voters to completely rank all candidates, by randomly breaking ties on candidates that are viewed as indifferent, leads to a reduction in the probability that a Condorcet winner exists and to a reduction in the Condorcet efficiency of all WSR's. Received: 31 July 1999/Accepted: 11 February 2000