Inferential properties of an individual-based survival model using release-recapture data: Sample size,validity and power

A model for analyzing release-recapture data is presented that generalizes a previously existing individual covariate model to include multiple groups of animals. As in the previous model, the generalized version includes selection parameters that relate individual covariates to survival potential. Significance of the selection parameters was equivalent to significance of the individual covariates. Simulation studies were conducted to investigate three inferential properties with respect to the selection parameters: (1) sample size requirements, (2) validity of the likelihood ratio test (LRT) and (3) power of the LRT. When the survival and capture probabilities ranged from 0.5 to 1.0, a total sample size of 300 was necessary to achieve a power of 0.80 at a significance level of 0.1 when testing the significance of the selection parameters. However, only half that (a total of 150) was necessary for the distribution of the maximum likelihood estimators of the selection parameters to approximate their asymptotic distributions. In general, as the survival and capture probabilities decreased, the sample size requirements increased. The validity of the LRT for testing the significance of the selection parameters was confirmed because the LRT statistic was distributed as theoretically expected under the null hypothesis, i.e. like a chi 2 random variable. When the baseline survival model was fully parameterized with population and interval effects, the LRT was also valid in the presence of unaccounted for random variation. The power of the LRT for testing the selection parameters was unaffected by over-parameterization of the baseline survival and capture models. The simulation studies showed that for testing the significance of individual covariates to survival the LRT was remarkably robust to assumption violations.     

Job Stability Trends,Lay‐offs,and Transitions to Unemployment in West Germany

This paper examines the evolution of different aspects of job stability, notably the termination reasons and the transition states. We estimate Semi‐Parametric Cox Hazard Models with competing risks for West Germany and find an increasing hazard of job ending that is driven by an increasing hazard of being laid off, primarily. One explanation found is that men with fixed‐term contracts face increasing risks of being displaced. In accordance with the technological change hypothesis we also find that men with a high degree of non‐routine interactive tasks face a declining risk of displacement.     

Measuring youth connections: A component of relational permanence for foster youth

This article presents the development and preliminary validation of the Youth Connections Scale, a measure of youth connectedness as a component of relational permanence for youth in out-of-home placement. The instrument measures different domains of youth's connectedness, including the number and strength of connections to caring adults and the types of support perceived by youth. Results of a pilot validation study of the instrument, with a sample of 53 adolescents in out-of-home care, indicate good concurrent validity and high test–retest reliability. Child welfare and youth-serving agencies can use this instrument in their efforts to strengthen and measure the connectedness and relational permanence of youth.     

Access to Health Care: Social Determinants of Preventive Cancer Screening Use in Northern British Columbia

The purpose of this study was to examine theextent to which social factors are influentialin determining women's access to cancerscreening services in Prince George, BritishColumbia. Specifically, this study evaluatedthe association of age, income, education, workstatus, disability, marital status, andimmigrant status with previous use of screeningmammography and Pap tests. Data was obtainedfrom the 1994 National Population HealthSurvey, which contains a sample of 416 womenfrom the Prince George area. A series oflogistic regression analyses were used todistinguish ever versus never beenscreened as well as recency of previousscreening. Participation rates in screeningmammography in Prince George are comparativelyhigh; however, no association was found betweensocial factors and previous mammography use.This suggests women in Prince George areparticipating in mammography servicesregardless of social background. Participationrates in Pap test screening in Prince Georgeare high and are similar to provincialaverages; however, while a large percentage ofwomen have been screened, this percentagevaries across social groups. Immigrant women,single women, and women with less education areover represented among women who have never hada Pap test. In addition, older women are lesslikely to obtain a recent Pap test whencompared to younger women. This study suggeststhat certain groups of women in northernBritish Columbia experience low participationin health services, resulting in a higher riskfor poor health and a poor quality of life.     

Making Sense of a Transnational Merger: Media Texts and the (Re)construction of Power Relations

In this study of symbolic power relations in a transnational merger, we suggest that the popular media can provide a significant arena for (re)constructing national identities and power in this kind of dramatic industrial restructuring, and are an under-utilized source of empirical data in research studies. Focusing on the press coverage of a recent Swedish-Finnish merger, we specify and illustrate a particular feature of discursive (re)construction of asymmetric power relations; superior (Swedish) and inferior (Finnish) national identities, which, we argue, are embedded in the history of colonization and domination between the two nations. The findings of the present study lead us to suggest that a lens taken from post-colonial theory is particularly useful in understanding the wider symbolic power implications of international industrial restructuring.     

Is ‘Candidacy’ a Useful Concept for Understanding Journeys through Public Services? A Critical Interpretive Literature Synthesis

Across the public sector there is concern that service uptake is inequitably distributed by socio‐economic circumstances and that public provision exacerbates the existence of inequalities either because services are not allocated by need or because of differential patterns of uptake between the most and least affluent groups. A concept that offers potential to understand access and utilization is ‘candidacy’ which has been used to explain access to, and utilization of, healthcare. The concept suggests that an individual's identification of his or her ‘candidacy’ for health services is structurally, culturally, organizationally and professionally constructed, and helps to explain why those in deprived circumstances make less use of services than the more affluent. In this article we assess the fit of candidacy to other public services using a Critical Interpretive Synthesis of three case studies literatures relating to: domestic abuse, higher education and environmental services. We find high levels of congruence between ‘candidacy’ and the sampled literatures on access/utilization of services. We find, however, that the concept needs to be refined. In particular, we distinguish between micro, meso and macro factors that play into the identification, sustaining and resolution of candidacy, and demonstrate the plural nature of candidacies. We argue that this refined model of candidacy should be tested empirically beyond and within health. More specifically, in the current economic context, we suggest that it becomes imperative to better understand how access to public services is influenced by multiple factors including changing discourses of deservedness and fairness, and by stringent reductions in the public purse.     

Die Soziologie und die Gesellschaft

Ohne Zusammenfassung     

Inferential properties of an individual-based survival model using release-recapture data: sample size, validity and power

A model for analyzing release-recapture data is presented that generalizes a previously existing individual covariate model to include multiple groups of animals. As in the previous model, the generalized version includes selection parameters that relate individual covariates to survival potential. Significance of the selection parameters was equivalent to significance of the individual covariates. Simulation studies were conducted to investigate three inferential properties with respect to the selection parameters: (1) sample size requirements, (2) validity of the likelihood ratio test (LRT) and (3) power of the LRT. When the survival and capture probabilities ranged from 0.5 to 1.0, a total sample size of 300 was necessary to achieve a power of 0.80 at a significance level of 0.1 when testing the significance of the selection parameters. However, only half that (a total of 150) was necessary for the distribution of the maximum likelihood estimators of the selection parameters to approximate their asymptotic distributions. In general, as the survival and capture probabilities decreased, the sample size requirements increased. The validity of the LRT for testing the significance of the selection parameters was confirmed because the LRT statistic was distributed as theoretically expected under the null hypothesis, i.e. like a chi 2 random variable. When the baseline survival model was fully parameterized with population and interval effects, the LRT was also valid in the presence of unaccounted for random variation. The power of the LRT for testing the selection parameters was unaffected by over-parameterization of the baseline survival and capture models. The simulation studies showed that for testing the significance of individual covariates to survival the LRT was remarkably robust to assumption violations.