排序方式: 共有43条查询结果,搜索用时 15 毫秒
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Stijn Luca 《Journal of applied statistics》2018,45(8):1447-1464
The purpose of acceptance sampling is to develop decision rules to accept or reject production lots based on sample data. When testing is destructive or expensive, dependent sampling procedures cumulate results from several preceding lots. This chaining of past lot results reduces the required size of the samples. A large part of these procedures only chain past lot results when defects are found in the current sample. However, such selective use of past lot results only achieves a limited reduction of sample sizes. In this article, a modified approach for chaining past lot results is proposed that is less selective in its use of quality history and, as a result, requires a smaller sample size than the one required for commonly used dependent sampling procedures, such as multiple dependent sampling plans and chain sampling plans of Dodge. The proposed plans are applicable for inspection by attributes and inspection by variables. Several properties of their operating characteristic-curves are derived, and search procedures are given to select such modified chain sampling plans by using the two-point method. 相似文献
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Tim Vantilborgh Stijn Van Puyvelde 《Voluntas: International Journal of Voluntary and Nonprofit Organizations》2018,29(1):29-42
The reliability of volunteers is a major concern for many nonprofit organizations. To address this problem in more detail, we develop a theoretical model of volunteer reliability based on psychological contract theory. By taking this perspective as a starting point, we explore how individual volunteer characteristics, organizational factors, and sociological developments shape the exchange of inducements and contributions between volunteers and nonprofit organizations. We discuss how these factors can create tensions in the psychological contract and determine the extent to which volunteers behave reliably. As such, we develop a theoretical framework for addressing the reliability problem in volunteer management. 相似文献
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Caroline Vandenplas Michèle Ernst Stähli Dominique Joye Alexandre Pollien 《Mathematical Population Studies》2017,24(2):103-125
ABSTRACTAdjustment 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. 相似文献
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The authors examined the hypothesis that many individuals define monogamy based on emotional rather than sexual fidelity. Participants, 373 heterosexual college students and 282 gay men, read three vignettes of decreasing mitigation in which they imagined committing an act of infidelity against a hypothetical partner and where half the participants were cued to their emotional attachment toward the partner. Despite the infidelity, relationships in the emotional attachment–cued vignettes were rated as monogamous to a greater degree than relationships in the vignettes where emotional attachment was not cued. In addition, over one-third of the participants in our study reported infidelity in their current self-defined monogamous relationships yet also reported feeling more protected from sexual health risks and reported less condom use than individuals who defined their relationship as nonmonogamous. The implications for monogamy as a protective fallacy are discussed. 相似文献
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Manoochehr Babanezhad Stijn Vansteelandt Els Goetghebeur 《Journal of statistical planning and inference》2010
Over the past decades, various principles for causal effect estimation have been proposed, all differing in terms of how they adjust for measured confounders: either via traditional regression adjustment, by adjusting for the expected exposure given those confounders (e.g., the propensity score), or by inversely weighting each subject's data by the likelihood of the observed exposure, given those confounders. When the exposure is measured with error, this raises the question whether these different estimation strategies might be differently affected and whether one of them is to be preferred for that reason. In this article, we investigate this by comparing inverse probability of treatment weighted (IPTW) estimators and doubly robust estimators for the exposure effect in linear marginal structural mean models (MSM) with G-estimators, propensity score (PS) adjusted estimators and ordinary least squares (OLS) estimators for the exposure effect in linear regression models. We find analytically that these estimators are equally affected when exposure misclassification is independent of the confounders, but not otherwise. Simulation studies reveal similar results for time-varying exposures and when the model of interest includes a logistic link. 相似文献
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Stijn Van Puyvelde Ralf Caers Cind Du Bois Marc Jegers 《Nonprofit management & leadership》2013,24(1):63-85
Most principal–agent literature of nonprofit organizations has focused on the relationship between board members and managers. However, in addition to the role as an agent of the board, the manager also performs a role as principal with respect to the nonprofit employees. By using a discrete choice experiment, we identify the objectives of managers and employees in nonprofit organizations and assess the presence of agency problems in this relationship. Our sample consists of 76 headmasters, 161 teachers, and 39 administrative employees in 74 secondary nonprofit schools in Belgium. We find that the six objectives set out in the experiment play an important role for both headmasters and subordinate staff. However, the results also indicate that some of these objectives are significantly more important for the headmasters. In sum, our results suggest that agency theory and stewardship theory are not necessarily in conflict with each other but can be combined into a more general governance framework for nonprofit organizations. Consequently, we argue that incentive structures that incorporate different types of objectives can facilitate the recruitment and retention of employees in nonprofit organizations. 相似文献
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We investigate whether volunteering has a causal effect on individual employment opportunities. To this end, a field experiment is conducted in which volunteering activities are randomly assigned to fictitious job applications sent to genuine vacancies in Belgium. We find that volunteers are 7.3 percentage points more likely to get a positive reaction to their job applications. The volunteering premium is higher for females but invariant with respect to the number of engagements. 相似文献
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Clara De Ruysscher Peter Tomlinson Stijn Vanheule Stijn Vandevelde 《Disability & Society》2019,34(5):797-818
While the recovery concept strongly resonates in clinical mental health care today, it first arose in service user-led contexts. A major risk of this professionalization shift is that recovery primarily becomes defined by treatment providers. This study aims to keep the debate on recovery alive through a collaborative exploration of Pete’s recovery process by means of a bricolage approach. This resulted in an idiographic portrait of Pete’s experiences of recovery and treatment, clustered around four themes: life rebuilding, identity, continuity of care and the role of drugs. His experiences illustrate a number of contradictions in the operationalization of the recovery ethos in today’s mental health care; whilst recovery appears as a hopeful vision of empowerment, it also risks being reduced to a tokenistic model that fails to address the social realities of people in recovery and in which the assumption that mental illness is chronic is still latently present. 相似文献
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Sara Rowaert Stijn Vandevelde Kurt Audenaert Gilbert Lemmens 《Australian and New Zealand Journal of Family Therapy》2018,39(2):186-199
This study investigates therapeutic factors of a Family Support Group (FSG) intervention for family members of mentally ill offenders. Seventeen family members completed the ‘Group Therapeutic Factors‐Client Questionnaire’ (GTF‐CQ‐28) during four sessions of two FSGs. Results indicate that family members experienced the following therapeutic factors over the course of treatment: the relational climate, interactional confirmation, expressing and experiencing mutual positive feelings, forgetting own problems, hope from seeing progress in others, guidance from therapists, and getting interpersonal feedback treatment. The therapeutic factors, including learning by observation, support from the group, and universality of problems, correlated with a decrease in self‐blame, improved emotional well‐being, and experiencing less loss of control over one's life, respectively. Further, family members were satisfied with what the FSG has provided for them personally and for the relation with their relative. Finally, clinical implications of the FSG are discussed. The study sheds light on valuable therapeutic factors within an FSG and the important role of therapists. 相似文献