The Limits of ex post Implementation

The sensitivity of Bayesian implementation to agents' beliefs about others suggests the use of more robust notions of implementation such as ex post implementation, which requires that each agent's strategy be optimal for every possible realization of the types of other agents. We show that the only deterministic social choice functions that are ex post implementable in generic mechanism design frameworks with multidimensional signals, interdependent valuations, and transferable utilities are constant functions. In other words, deterministic ex post implementation requires that the same alternative must be chosen irrespective of agents' signals. The proof shows that ex post implementability of a nontrivial deterministic social choice function implies that certain rates of information substitution coincide for all agents. This condition amounts to a system of differential equations that are not satisfied by generic valuation functions.     

Factor structure of quality of life: The Lehman interview

This study of 67 chronically mentally ill outpatients with psychotic disorders examined subjective quality of life scores from Lehman's Quality of Life (QOL) interview. Factor analyses identified ‘Affiliative’ and ‘Instrumental’ dimensions which accounted for 67% of the variance in subjective satisfaction ratings. The results suggest a model in which instrumental and affiliative needs comprise significant portions of subjective life satisfaction and that global QOL satisfaction is related more to instrumental than affiliative needs. These findings further clarify the concept of life satisfaction in this population of severely mentally ill individuals and suggest modifications in how quality of life information is evaluated.     

On Criteria of Insignificant Difference Between Two Risks

The comparison and ranking of risks is very important for safety and cost-benefit analysis. Most formats present risks in the form of probability distribution. Different ranking criteria for probability distributions are considered. It is demonstrated that significantly overlapping distributions lead to ambiguous results. For this reason, criteria of insignificant overlapping distributions are proposed. The first criterion uses the information theory approach; and the second criterion uses the statistical tests approach. Both approaches can be applied to decision theory to avoid questionable decisions based on statistically insignificant differences between two risks.     

Low Social Status Markers: Do They Predict Depressive Symptoms in Adolescence?

Some markers of social disadvantage are associated robustly with depressive symptoms among adolescents: female gender and lower socioeconomic status (SES), respectively. Others are associated equivocally, notably black v. white race/ethnicity. Few studies examine whether markers of social disadvantage by gender, SES, and race/ethnicity jointly predict self-reported depressive symptoms during adolescence; this was our goal. Secondary analyses were conducted on data from a socioeconomically diverse community-based cohort study of non-Hispanic black and white adolescents (N = 1,263, 50.4% female). Multivariable general linear models tested whether female gender, black race/ethnicity, and lower SES (assessed by parent education and household income) and their interactions predicted greater depressive symptoms reported on the Center for Epidemiological Studies Depression Scale. Models adjusted for age and pubertal status. Univariate analyses revealed more depressive symptoms in females, blacks, and participants with lower SES. Multivariable models showed females across both racial/ethnic groups reported greater depressive symptoms; blacks demonstrated more depressive symptoms than did whites, but when SES was included this association disappeared. Exploratory analyses suggested blacks gained less mental health benefit from increased SES. However, there were no statistically significant interactions among gender, race/ethnicity, or SES. Taken together, we conclude that complex patterning among low social status domains within gender, race/ethnicity, and SES predicts depressive symptoms among adolescents.     

How to make head or tail of ‘bridging’ and ‘bonding’?: addressing the methodological ambiguity1

A distinction has recently been proposed between bridging (or encompassing) and bonding (or inward-looking) social networks. However, existing theoretical contributions remain vague as to the fundamental meaning of both concepts. As a consequence, two distinct interpretations have developed alongside each other. In the present paper, we employ data on voluntary association membership in Flanders to empirically illustrate that both approaches can lead to substantially different outcomes and therefore appear to tap into different dimensions of bridging versus bonding. These findings underline the problematic nature of the current conceptual ambiguity. We conclude that should the bridging/bonding distinction add meaningfully to our understanding of the external effects of social networks, it is essential to resolve the conceptual and methodological imprecision.