The effect of using labelled alternatives in stated choice experiments: an exploration focusing on farmland walking trails in Ireland

Discrete choice experiment data aimed at eliciting the demand for recreational walking trails on farmland in Ireland is used to explore whether some respondents reach their choices solely on the basis of the alternative’s label. To investigate this type of processing strategy, the paper exploits a discrete mixtures approach which encompasses random parameters for the attributes. We find evidence that respondents employ different processing strategies for different alternatives and differences in processing emerge between rural and urban based respondents. Results highlight that model fit and policy conclusions are sensitive to assumptions related to processing strategies among respondentsDiscrete choice experiments, processing strategies, discrete mixtures, rural and urban comparison, outdoor recreation, welfare estimates, Land Economics/Use,

Combining discrete and continuous mixing approaches to accommodate heterogeneity in price sensitivities in environmental choice analysis

Data from a discrete choice experiment aimed at eliciting the demand for recreational walking trails on farmland in the Republic of Ireland is used to explore the consequences of misspecifying the cost coefficient. To enable straightforward calculation of WTP from the distributions of the non-price coefficients, the price coefficient is typically held constant in mixed logit models. This implies that all respondents are equally price sensitive. In this paper we test the validity of this assumption. Our approach is based on a comparison and combination of discrete and continuous mixing approaches (i.e., a mixture of distributions) to uncover the unobserved heterogeneity in price sensitivities. Results from the analysis highlight that model fit and willingness to pay are sensitive to the distributional assumptions used to represent the price coefficient.discrete choice experiments, discrete mixtures, continuous mixtures, mixtures of distributions, price sensitivities, farmland recreation, willing to pay space, Environmental Economics and Policy,

Public access to the countryside: An exploration of the costs and benefits of farmland walking trails

To date, estimates of individuals’ willingness to pay (WTP) for access to the countryside have typically been on sites of special interest such as developed walking routes, public rights of way in specific areas, national parks and forests (see Lockwood and Tracy, 1995; Bennett and Tranter, 1997; Crabtree and MacDonald, 1997; Liston-Heyes and Heyes, 1999; Garrod et al., 1998; Bennett et al., 2003; Buckley et al., 2009; Morris et al., 2009). There has been little if any attempt to derive estimates of individuals’ WTP for the provision of walking trails in the wider countryside at a national level. The present study aims to build on previous work by examining the demand for particular types of walking trails through a nationally representative survey of the Irish population. One further advantage of this research is that apart from valuing walking activities in a generic sense this paper investigates what types of investment in facilities associated with walking trails generate the greatest welfare gains. Furthermore, using a nationally representative survey of the farming population this paper examines farmers’ willingness to participate in a hypothetical walking scheme whereby the general public will be allowed access to specific trails. First by way of background this paper will discuss the situation in relation to access rights to the countryside across a number of countries. Second this paper will outline the research approach which is followed with a discussion of the empirical results. Finally this paper will conclude with a discussion of the papers main findings and their implications for the provision of public access to the countryside.This work was funded by the Department of Agriculture, Fisheries and Food under the Stimulus Funding

Imported falciparum malaria among adults requiring intensive care: analysis of the literature.

BACKGROUND: Malaria is the most important imported tropical disease. Infection with Plasmodium falciparum is responsible for most of the morbidity and mortality. There are differences in both the epidemiology of imported malaria and in the facilities available to treat travellers with severe malaria between different parts of the world. There are limited data to guide clinicians caring for adults with imported malaria in an intensive care unit (ICU). Available data from the English-speaking literature concerning such patients was reviewed. METHODS: PubMed was searched for studies on adults with imported malaria treated in an ICU. Data were extracted on the epidemiology, management, rates of concomitant community-acquired bacterial infection and outcomes. RESULTS: Thirteen studies were identified, which between them included 1,001 patients over more than 40 years. Forty-one per cent were born and often still resident in an endemic country and were assumed to have at least partial immunity to the disease. Acute kidney injury (AKI) (36%), acute respiratory distress syndrome (ARDS) (31%) and impaired consciousness (25%) were common. Hyperparasitaemia (more than 2%) was seen in 57%. Thirty-four per cent required mechanical ventilation and 22% required renal replacement therapy. Community-acquired bacterial co-infection was seen in 8%; 2% had gram-negative bacteraemia at admission. Overall the case fatality rate was 9%. CONCLUSIONS: Many patients who require admission to ICU were originally from malaria-endemic countries and many did not have hyperparasitaemia. Gram-negative bacteraemia was uncommon among adults with severe malaria. The case fatality rate remains high; however, improvements in ICU care and increasing use of artemisinins may reduce this in the future

Gametocyte carriage in Plasmodium falciparum-infected travellers.

BACKGROUND: Gametocytes are the sexual stage of Plasmodium parasites. The determinants of gametocyte carriage have been studied extensively in endemic areas, but have rarely been explored in travellers with malaria. The incidence of gametocytaemia, and factors associated with gametocyte emergence in adult travellers with Plasmodium falciparum malaria was investigated at the Hospital for Tropical Diseases in London. METHODS: Clinical, parasitological and demographic data for all patients presenting with P. falciparum malaria between January 2001 and December 2011 were extracted from a prospective database. These data were supplemented by manual searches of laboratory records and patient case notes. RESULTS: Seven hundred and seventy three adult patients with laboratory-confirmed P. falciparum malaria were identified. Four hundred and sixty five (60%) were born in a country where malaria is endemic. Patients presented to hospital a median of four days into their illness. The median maximum parasite count was 0.4%. One hundred and ninety six patients (25%) had gametocytes; 94 (12%) on admission, and 102 (13%) developing during treatment. Gametocytaemia on admission was associated with anaemia and a lower maximum parasitaemia. Patients with gametocytes at presentation were less likely to have thrombocytopenia or severe malaria. Patients who developed gametocytes during treatment were more likely to have had parasitaemia of long duration, a high maximum parasitaemia and to have had severe malaria. There was no apparent association between the appearance of gametocytes and treatment regimen. CONCLUSIONS: The development of gametocytaemia in travellers with P. falciparum is associated with factors similar to those reported among populations in endemic areas. These data suggest that acquired immunity to malaria is not the only determinant of patterns of gametocyte carriage among patients with the disease

The effect of using labelled alternatives in stated choice experiments: an exploration focusing on farmland walking trails in Ireland

Discrete choice experiment data aimed at eliciting the demand for recreational walking trails on farmland in Ireland is used to explore whether some respondents reach their choices solely on the basis of the alternative's label. To investigate this type of processing strategy, the paper exploits a discrete mixtures approach which encompasses random parameters for the attributes. We find evidence that respondents employ dierent processing strategies for dierent alternatives and dierences in processing emerge between rural and urban based respondents. Results highlight that model fit and policy conclusions are sensitive to assumptions related to processing strategies among respondents

What's in a name? Identifying and accommodating labelling effects withindiscrete choice experiments

Discrete choice experiment data aimed at eliciting the demand for recreational walking trails on farmland in Ireland is used to explore whether some respondents reach their choices solely on the basis of the alternatives label. To investigate this type of processing strategy, the paper exploits a discrete mixtures approach which encompasses random parameters for the attributes. We find evidence that respondents employ different processing strategies for different alternatives and differences in processing emerge between rural and urban based respondents. Results highlight that model fit and policy conclusions are sensitive to assumptions related to processing strategies among respondents

Hyperreactive Malarial Splenomegaly Syndrome--Can the Diagnostic Criteria Be Improved?

Hyperreactive Malarial Splenomegaly Syndrome (HMSS) was described and defined before sensitive tests for malaria were available. We present a series of seven individuals who were referred to our clinics with possible HMSS. Chronic malaria was demonstrated in those successfully treated but not in those who failed to respond to therapy. This observation suggests that the newer molecular malaria assays have a role to play in the identification of individuals who are likely to respond to treatment for HMSS in non-endemic regions