133,934 research outputs found
Se non ci credete non me ne importa
No full textNella postfazione si identificano e approfondiscono alcuni temi della raccolta Storie naturali
The value of collective reputation for environmentally-friendly production methods: The case of Val di Gresta
No full textIn this paper we investigate consumers' preferences for various environment-friendly production systems for carrots. We use discrete-choice multi-attribute stated-preference data to explore the effect of collective reputations from growers of an Alpine valley known for its environment-friendly production: Val di Gresta 'the valley of organic orchards'. Data analysis of the panel of discrete responses identifies unobserved taste heterogeneity for organic, bio-dynamic and place of origin, while observed heterogeneity for income is addressed by a piece-wise linear function. The implied sample distributions of individual-specific WTP for each of these random attributes are then compared. Results indicate that Integrated Pest Management is preferred to biodynamic as an emerging method. The presence of a premium for Val di Gresta produce is confirmed. The use of an experimental design to identify the relevant second order effects reveals the presence of a reputation effect which can be decomposed into a generic effect from place of origin and a specific one for each EFPMs. Farmers operating in geographically limited marginal areas, such as mountain valleys, may find it useful to invest in collective reputation through high quality standard to achieve higher returns. This strategy may compensate for the dwindling public support to farm income from EU programmes
Incorporating Discontinuous Preferences into the Analysis of Discrete Choice Experiments
No full textDiscontinuous preferences, Discrete choice experiments, Multinomial error component logit model, Rural environmental landscapes, Willingness to pay,
Benefit estimates for landscape improvements: sequential Bayesian design and respondents’ rationality in a choice experiment
No full textA multi-attribute, stated-preference approach is used to value low and high impact actions on four major landscape components addressed by the Rural Environment Protection Scheme in Ireland. Several methodological issues are addressed: the use of prior beliefs on the relative magnitudes of parameters, standardized description of different levels of landscape improvements via image manipulation software, adoption of efficiency-increasing sequential experimental design, and sensitivity of benefit estimates to inclusion of responses from "irrational" respondents. Results suggest that Bayesian design updating delivers significant efficiency gains without loss in respondent efficiency, and estimates are upward-biased when irrational respondents are included
Does respondent perception of the status quo matter in non-market valuation with choice experiments? An application to New Zealand freshwater streams
No full textIn environmental valuation studies with stated preference methods, researchers often provide descriptions of status quo conditions which may differ from those perceived by respondents. Ignoring this difference in utility baselines may affect the magnitude of utility changes and hence bias the implied estimates of benefits from the proposed environmental policies. We investigate this issue using data from a choice experiment on a community’s willingness to pay for water quality improvements in streams. More than 60 percent of respondents perceived the description of the quality of water in streams to be better than the one we provided in our scenario. Our results show that respondents who could provide details of their perception of the status quo displayed stronger preferences for water quality improvements - hence a higher marginal willingness to pay - than their counterparts. Respondents who opted for their own status quo description displayed a higher inclination to remain in the status quo, while their counterparts displayed the contrary. We argue this might be linked to the amount of knowledge each group displayed about the status quo: a kind of reluctance to leave what one knows well
Using Flexible Taste Distributions to Value Collective Reputation for Environmentally Friendly Production Methods
No full text"In this paper, we investigate consumer preferences for various environmentally friendly production systems for carrots. We use discrete choice multi-attribute stated preference data to explore the effect of the collective reputation of growers from an Alpine valley with an established reputation for its environmentally friendly production: Val di Gresta 'the valley of organic orchards.' Data analysis of the panel of discrete responses identifies unobserved taste heterogeneity for organic, biodynamic, and place of origin along with extra variance associated with experimentally designed alternatives. The assumed parametric taste distributions are each tested using the semi-nonparametric specification proposed by Fosgerau and Bierlaire, while the null of normality cannot be rejected for organic and biodynamic production methods, though it is for the place of origin. The latter is found to be bi-modal, with modes at each side of zero. The use of a flexible taste distribution increases the plausibility of this form of heterogeneity and it appears promising for future applied studies." Copyright (c)2008 Canadian Agricultural Economics Society.
Scarpa da Calcio
No full textLa presente invenzione si riferisce ad una calzatura o
scarpa, particolarmente concepita per l’utilizzo sportivo
per esempio per il gioco del calcio. La calzatura comprende
una suola (301, 401, 501) che comprende una porzione
anteriore ed una porzione posteriore; la porzione anteriore
comprende una pluralità di tacchetti (202) ciascuno
comprendente un corpo rastremato sporgente dalla suola. La
pluralità di tacchetti (202) della porzione anteriore
comprende un tacchetto centrale (203) ed una pluralità di
tacchetti periferici (304, 305, 307, 402, 403, 502) i cui
corpi hanno sezioni con profilo curvilineo e
sostanzialmente concentrico rispetto al tacchetto centrale
(203)
Experimental designs for environmental valuation with choice-experiments: A Monte Carlo investigation
No full textWe review the practice of experimental design in the environmental economics literature concerned with choice experiments. We then contrast this with advances in the field of experimental design and present a comparison of statistical efficiency across four different experimental designs evaluated by Monte Carlo experiments. Two different situations are envisaged. First, a correct a priori knowledge of the multinomial logit specification used to derive the design and then an incorrect one. The data generating process is based on estimates from data of a real choice experiment with which preference for rural landscape attributes were studied. Results indicate the D-optimal designs are promising, especially those based on Bayesian algorithms with informative prior. However, if good a priori information is lacking, and if there is strong uncertainty about the real data generating process - conditions which are quite common in environmental valuation - then practitioners might be better off with conventional fractional designs from linear models. Under misspecification, a design of this type produces less biased estimates than its competitors
La carne d'Europa. Benedetto Croce recensice "La carne, la morte e il diavolo" di Mario Praz
No full textCost thresholds, cut-offs and sensitivities in stated choice analysis: identification and implications
No full textWithin the discrete choice literature, there is growing recognition that some respondents do not process all attributes when evaluating their choice outcomes. Worryingly, the cost attribute is often among those attributes that are likely to be ignored by respondents. We use probabilistic decision process models (similar in form to latent class models, but where we define the classes to describe specific heuristics) to facilitate situations where respondents adopt cost thresholds and cut-offs. We further develop this model to address the potential confounding between preference heterogeneity and processing heterogeneity by simultaneously allowing for a segmentation of respondents based on their sensitivities to cost. Results, based on an empirical dataset on the existence value of rare fish species in Ireland, provide further confirmation that a share of respondents did not attended to cost. Importantly, however, when heterogeneity to cost levels is accounted for the inferred incidence of complete non-attendance is markedly lower, to the extent that when cost thresholds and cut-offs are also accommodated it almost disappears. This modelling approach leads to significant gains in model fit and has important implications for welfare analysis
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