The potential of integrated modelling in conservation biology: A case study of the black‐footed albatross (Phoebastria nigripes)

Conservation biology aims at assessing the status of a population, based on information which is often incomplete. Integrated population modelling based on state‐space models appears to be a powerful and relevant way of combining into a single likelihood several types of information such as capture‐recapture data and population surveys. In this paper, the authors describe the principles of integrated population modelling and they evaluate its performance for conservation biology based on a case study, that of the black‐footed albatross, a northern Pacific albatross species suspected to be impacted by longline fishing     

Adjustment for nonresponse with variables from different sources: Bias correction and precision loss,with application to the Swiss European Social Survey 2012

ABSTRACT

Adjustment for nonresponse should reduce the nonresponse bias without decreasing the precision of the estimates. Adjustment for nonresponses are commonly based on socio-demographic variables, although these variables may be poorly correlated with response propensities and with variables of interest. Such variables nevertheless have the advantage of being available for all sample units, whether or not they are participating in the survey. Alternatively, adjustment for nonresponse can be obtained from a follow-up survey aimed at sample units which did not participate in the survey and from which the variables are designed to be correlated with response propensities. However, information collected through these follow-up surveys is not available for people in the sample who participated neither in the survey nor in its nonresponse follow-up. These two sets of variables when used in a nonresponse model for the Swiss European Social Survey 2012 differ only slightly with regard to their effect on bias correction and on the precision of estimates. The variables from the follow-up are performing slightly better. In both cases, the adjustment for nonresponse performs poorly.     

Child Obesity and the Interaction of Family and Neighborhood Socioeconomic Context

Population Research and Policy Review - The literature on neighborhoods and child obesity links contextual conditions to risk, assuming that if place matters, it matters in a similar way for...     

How to measure and proxy permanent income: evidence from Germany and the U.S.

Permanent income (PI) is an enduring concept in the social sciences and is highly relevant to the study of inequality. Nevertheless, there has been insufficient progress in measuring PI. We calculate a novel measure of PI with the German Socio-Economic Panel (SOEP) and U.S. Panel Study of Income Dynamics (PSID). Advancing beyond prior approaches, we define PI as the logged average of 20+ years of post-tax and post-transfer (“post-fisc”) real equivalized household income. We then assess how well various household- and individual-based measures of economic resources proxy PI. In both datasets, post-fisc household income is the best proxy. One random year of post-fisc household income explains about half of the variation in PI, and 2–5 years explain the vast majority of the variation. One year of post-fisc HH income even predicts PI better than 20+ years of individual labor market earnings or long-term net worth. By contrast, earnings, wealth, occupation, and class are weaker and less cross-nationally reliable proxies for PI. We also present strategies for proxying PI when HH post-fisc income data are unavailable, and show how post-fisc HH income proxies PI over the life cycle. In sum, we develop a novel approach to PI, systematically assess proxies for PI, and inform the measurement of economic resources more generally.     

Going solo: Findings from a survey of women aging without a partner and who do not have children

Greater longevity in the UK population has led to the increasing diversity of women experiencing aging in a multitude of ways. Internationally, gender inequalities in aging are still relatively invisible within both government policy and everyday life for particular groups of women. This article explores the concept of women growing older “solo”—by which we mean women who find themselves nonpartnered and aging without children as they move into later life. We report on the findings from a mixed-methods survey of 76 solo women in the UK aged 50 years and over, used to provide a broader overview of the issues and challenges they face as they move into later life. Qualitative data from the survey captured respondents’ perspectives about the links between their relationships status and well-being in later life and highlighted specific cumulative disadvantages emerging for some women as a result of their solo lifestyles. We discuss two key themes that were identified, “solo-loneliness” and “meaningful futures,” in conjunction with the relevant literature and make suggestions for future research within gender and aging studies that could enhance more positive approaches to solo lifestyles.     

Using Eye Tracking to Identify Faking Attempts During Penile Plethysmography Assessment

Penile plethysmography (PPG) is considered the most rigorous method for sexual interest assessment. Nevertheless, it is subject to faking attempts by participants, which compromises the internal validity of the instrument. To date, various attempts have been made to limit voluntary control of sexual response during PPG assessments, without satisfactory results. This exploratory research examined eye-tracking technologies' ability to identify the presence of cognitive strategies responsible for erectile inhibition during PPG assessment. Eye movements and penile responses for 20 subjects were recorded while exploring animated human-like computer-generated stimuli in a virtual environment under three distinct viewing conditions: (a) the free visual exploration of a preferred sexual stimulus without erectile inhibition; (b) the viewing of a preferred sexual stimulus with erectile inhibition; and (c) the free visual exploration of a non-preferred sexual stimulus. Results suggest that attempts to control erectile responses generate specific eye-movement variations, characterized by a general deceleration of the exploration process and limited exploration of the erogenous zone. Findings indicate that recording eye movements can provide significant information on the presence of competing covert processes responsible for erectile inhibition. The use of eye-tracking technologies during PPG could therefore lead to improved internal validity of the plethysmographic procedure.     

Addressing potential prior‐data conflict when using informative priors in proof‐of‐concept studies

Bayesian methods are increasingly used in proof‐of‐concept studies. An important benefit of these methods is the potential to use informative priors, thereby reducing sample size. This is particularly relevant for treatment arms where there is a substantial amount of historical information such as placebo and active comparators. One issue with using an informative prior is the possibility of a mismatch between the informative prior and the observed data, referred to as prior‐data conflict. We focus on two methods for dealing with this: a testing approach and a mixture prior approach. The testing approach assesses prior‐data conflict by comparing the observed data to the prior predictive distribution and resorting to a non‐informative prior if prior‐data conflict is declared. The mixture prior approach uses a prior with a precise and diffuse component. We assess these approaches for the normal case via simulation and show they have some attractive features as compared with the standard one‐component informative prior. For example, when the discrepancy between the prior and the data is sufficiently marked, and intuitively, one feels less certain about the results, both the testing and mixture approaches typically yield wider posterior‐credible intervals than when there is no discrepancy. In contrast, when there is no discrepancy, the results of these approaches are typically similar to the standard approach. Whilst for any specific study, the operating characteristics of any selected approach should be assessed and agreed at the design stage; we believe these two approaches are each worthy of consideration. Copyright © 2015 John Wiley & Sons, Ltd.