Harmful algal bIoom species are the cause of important damages to marine living resources and human beings. These marine species are primarily introduced in North-European waters through ballast water, i.e. water trans-ported across the oceans so as to keep a vessel in balance. Port authorities...

The sample selection model is based upon a bivariate or a multivariate structure, and distributional assumptions are in this context more severe than in univariate settings, due to the limited availability of tractable multivariate distributions. While the standard FIML estimation of the...

The aim of the paper is twofold: to carry out a contingent valuation study of "Napoli Musei Aperti", a cultural public good provided by the city of Naples, and to explore some alternative schemes of cultural policy. The paper is divided in two parts. In the first one some results from the...

The Dichotomous Choice Contingent Valuation Method can be used either in the single or double bound formulation. The former is easier to implement, while the latter is known to be more efficient. We analyse the bias of the ML estimates produced by either model, and the gain in efficiency...

Respondents of contingent valuation surveys may place a null value on the public good, for reasons that differ from a genuine indifference to the good, but that can be interpreted as a "protest": either against the interview, or the public management, or both. A good survey design can...

When modelling data generated from a discrete choice contingent valuation question, the treatment of zero bids affects the welfare estimates. Zero bids may come from respondents who are not interested in the provision of the public good; alternatively, some zero-bidders may be protesting about...

Selectivity bias caused by protest responses in Contingent Valuation studies can be detected and corrected by means of sample selection models. This paper compares two methods: the Heckman 2-steps method and the full ML, applied to data on forest recreation - where WTP is elicited as a...

I derive the marginal value of a public good in multiperson households, measured alternatively by one household member’s willingness to pay (WTP) for the good on behalf of the household, or by the sum of individual WTP values across family members. Households are assumed to allocate their...

I derive values of marginal changes in a public good for two-person households, measured alternatively by household member i's willingness to pay (WTP) for the good on behalf of the household, WTPi(H), or by the sum of individual WTP values across family members, WTP(C). Households are assumed...

The sample selection model is based upon a bivariate or a multivariate structure, and distributional assumptions are in this context more severe than in univariate settings, due to the limited availability of tractable multivariate distributions. While the standard FIML estimation of the...