Embedding effects: Stimulus representation and response mode

Thecontingent valuation (CV) methodology assigns prices to environmental amenities by asking people how much they would be willing to pay in order to preserve or acquire those amenities. If this measurement procedure is valid, then responses should be sensitive to relevant changes in the amenities being judged and insensitive to irrelevant changes. One apparent demonstration of inappropriate insensitivity is theembedding effect: the observation that people are apparently willing to pay the same amount of money for a good as for a minor subset of that good. This study examined the possibility that the source of this effect lies with each of two (potentially treatable) methodological problems: 1) subjects have difficulty using quantitative (dollar) response modes to express their values; and 2) subjects have difficulty absorbing the essential details of the CV scenarios describing those goods. The study found that 1) subjects showed considerable embedding both with a simple paired-comparison response mode and with a more demanding one requiring direct dollar estimates; 2) embedding was much reduced with the simpler response mode; 3) subjects' preferences with the two response modes were usually inconsistent; 4) when asked to describe the CV scenario that they had just heard, subjects often reported key task details inaccurately; and 5) there was less embedding when tasks were reinterpreted in terms of the questions subjects reported having answered (as opposed to what had actually been asked). These results are discussed in terms of the match between the questions that investigators would like to ask and the ones that subjects are capable of answering.     

Wealth,Race, and Mortality*

Objective. We explore, first, whether wealth relates to mortality risk independent of income and education, and second, whether wealth closes the black‐white gap in U.S. adult mortality while controlling for other socioeconomic and sociodemographic factors. Methods. We employ the Cox proportional hazards models on data from the 1992 wave of the Health and Retirement Study linked to deaths through 1998, to analyze pre‐retirement adult mortality in the United States. Results. The findings suggest that broader measures of SES, including wealth, are significant for understanding adult mortality. Further, vastly lower asset holdings among blacks, compared to whites, not only affects their financial well‐being but also their survival prospects. Conclusions. Research and social policies that aim to understand and close health disparities in the United States may be poorly conceived if they ignore the impact of wealth on premature adult mortality.     

A stress process model of family caregiver service utilization: factors associated with respite and counseling service use

This study examines whether caregivers' differential utilization of respite and counseling support services is associated with different situational stress processes. A multinomial regression analysis was conducted to compare respite users, counseling users, and those who used neither service, using data collected on a statewide random sample of 1,643 California caregivers providing assistance to individuals aged 50 or older. Compared with caregivers who used neither service, respite service users were more likely to have demanding care situations giving rise to physical symptoms of stress, and were more likely to use community services for the care recipient to augment their care. In contrast, counseling service users were more likely to be managing the meaning of their care situation by seeking out information about services and talking with a confidant about their situation, while coping with both emotional and physical symptoms of stress. Tailoring caregiver interventions to meet the support needs and coping strategies stemming from diverse caregiving situations and caregiver characteristics may increase the likelihood that those interventions will be effective in alleviating or preventing deleterious secondary stress frequently experienced by family caregivers.     

Randomized response multivariate designs for categorical data

Three approaches to multivariate estimation for categorical data using randomized response (RR) are described. In the first approach, practical only for 2×2 contingency tables, a multi-proportions design is used. In the second approach, a separate RR trial is used for each variate and it is noted that the multi­variate design matrix of conditional probabilities is given by the Kroneeker product of the univariate design matrices of each trial, provided that the trials are independent of each other in a certain sense. The third approach requires only a single randomization and thus may be viewed as the use of vector response. Finally, a special-purpose bivariate design is presented.     

Bayesian estimation of proportions with a cross-entropy prior

This paper suggests estimators of the frequencies (N₈) or proportions {N₈/N) of N distinguishable objects contained in S categories; given various types of information, We consider information in the form of exact constraints on the N₈, sample frequencies, and frequencies of related data, The analysis uses Bayesian methods, where the prior distribution is assumed to be a function of the cross-entropy between the N₈ and a reference distribution, We show the relationship between our estimator and the log-linear and logit models and also present a sampling experiment to compare our proposed estimator with the iterated proportional fitting estimator.     

Application of ordinal correspondence analysis for submerged aquatic vegetation monitoring

The European Water Framework states that macrophyte communities (seaweeds and seagrass) are key indicators of the ecological health of lagoons. Furthermore, the restoration of these communities, especially the Zostera meadows, is one of the main objectives of the Berre lagoon restoration plan. Consequently, a monitoring programme of the main macrophyte species still present in the lagoon was initiated in 1996. This monitoring resulted in a sequence of 11 spatially structured annual tables consisting of the observed density of these species. These tables are processed in this study. First, we specify the principles of Beh's ordinal correspondence analysis (OCA), designed for ordered row/column categories, and compare this method to classical correspondence analysis (CA). Then, we show that OCA is straightforwardly adaptable for processing a sequence of ordered contingency tables like ours. Both OCA and CA are afterwards used to reveal and test the main patterns of spatio-temporal changes of two macrophyte species in the Berre lagoon: Ulva and Zostera. The results we obtained are compared and discussed.     

Bareback sex and the law: the difficult issue of HIV status disclosure

1. Unsafe anal intercourse (bareback sex) is on the rise within the gay community. 2. Barebacking constitutes a sexual practice with strong HIV-related legal implications. Nurses need to be aware of public health laws to be able to protect clients from undue legal prosecution. 3. Nurses need to be aware of the components of HIV pretest counseling. 4. Adopting a nonjudgmental, matter-of-fact approach is essential in establishing effective therapeutic relationships with clients who engage in bareback sex.     

An introduction to methodological challenges in the evaluation of eHealth research: Perspectives from the Health e-Technologies Initiative

In February 2002 the Health e-Technologies Initiative (HETI), a program office of the Robert Wood Johnson Foundation^®, was created to advance discovery of scientific knowledge regarding the effectiveness of interactive eHealth applications. This article is the introduction to a series of seven articles written by grantees of HETI which address challenges, lessons learned, and proposed solutions as researchers implement eHealth projects. From this body of work it is clear that the overall process of conducting evaluation research in eHealth requires careful and detailed planning, recognition of the heightened sensitivity of IRBs, and institutions around the electronic collection and communication of personal health information, and a combination of tenacity and creativity to address the inevitable thorny methodological challenges to eHealth research. Use of established guidelines to help standardize the evaluation process, where feasible, is recommended.