Setting tolerance limits for statistical project control using earned value management

Project control has been a research topic since decades that attracts both academics and practitioners. Project control systems indicate the direction of change in preliminary planning variables compared with actual performance. In case their current project performance deviates from the planned performance, a warning is indicated by the system in order to take corrective actions.Earned value management/earned schedule (EVM/ES) systems have played a central role in project control, and provide straightforward key performance metrics that measure the deviations between planned and actual performance in terms of time and cost. In this paper, a new statistical project control procedure sets tolerance limits to improve the discriminative power between progress situations that are either statistically likely or less likely to occur under the project baseline schedule. In this research, the tolerance limits are derived from subjective estimates for the activity durations of the project. Using the existing and commonly known EVM/ES metrics, the resulting project control charts will have an improved ability to trigger actions when variation in a project׳s progress exceeds certain predefined thresholdsA computational experiment has been set up to test the ability of these statistical project control charts to discriminate between variations that are either acceptable or unacceptable in the duration of the individual activities. The computational experiments compare the use of statistical tolerance limits with traditional earned value management thresholds and validate their power to report warning signals when projects tend to deviate significantly from the baseline schedule.     

Quality and Reliability in Top-event Estimation: Quantitative Fault Tree Analysis in Case of Dependent Events

This article deals with the quantitative Fault Tree Analysis (FTA) and the estimation method of the top-event in case of dependent events. It aims at addressing two main issues: (1) the decomposition of variability for the top-event according to several error components linked to the estimation of the top-event and sources of internal and external variations for a complex system; and (2) the definition of a Performance Measure Independent of Adjustment in order to set the quality of the top-event as a complex measure of the system failure. A simulated study applied to the health system is also carried out.     

论社会企业的合法性

社会企业的组织形态与现行法律体系格格不入,产品受到公众质疑,定位受限于一线城市,导致在法规合法性、道德合法性与认知合法性等方面面临难题,并进而影响社会企业的经济效益与社会效益。鉴于此,唯有通过主动地适应或选择、改变或创造环境才能化解这一难题。     

大学生心理危机的识别与预警

心理危机的识别与预警既是预防心理危机发生的重要策略，也是对危机当事人和相关人进行生命教育和促进生命成长的重要机会。心理危机产生的原因具有复杂性，发生过程具有阶段性，危机现象具有特殊性，危机爆发具有极端性，危机发生也具有一定规律性。因此，在进行生命教育过程中，需要关注不同类别的生命个体、不同阶段的生命现象、处在规律中的独特生命个体，同时要注意识别生命危机信号和生命求救信号。     

On the Identification and Early Warning of College Students＇ Psychological Crisis from the Perspectiveof Life Education

心理危机的识别与预警既是预防心理危机发生的重要策略，也是对危机当事人和相关人进行生命教育和促进生命成长的重要机会。心理危机产生的原因具有复杂性，发生过程具有阶段性，危机现象具有特殊性，危机爆发具有极端性，危机发生也具有一定规律性。因此，在进行生命教育过程中，需要关注不同类别的生命个体、不同阶段的生命现象、处在规律中的独特生命个体，同时要注意识别生命危机信号和生命求救信号。     

A Tiered Framework for Risk‐Relevant Characterization and Ranking of Chemical Exposures: Applications to the National Children's Study (NCS)

A challenge for large‐scale environmental health investigations such as the National Children's Study (NCS), is characterizing exposures to multiple, co‐occurring chemical agents with varying spatiotemporal concentrations and consequences modulated by biochemical, physiological, behavioral, socioeconomic, and environmental factors. Such investigations can benefit from systematic retrieval, analysis, and integration of diverse extant information on both contaminant patterns and exposure‐relevant factors. This requires development, evaluation, and deployment of informatics methods that support flexible access and analysis of multiattribute data across multiple spatiotemporal scales. A new “Tiered Exposure Ranking” (TiER) framework, developed to support various aspects of risk‐relevant exposure characterization, is described here, with examples demonstrating its application to the NCS. TiER utilizes advances in informatics computational methods, extant database content and availability, and integrative environmental/exposure/biological modeling to support both “discovery‐driven” and “hypothesis‐driven” analyses. “Tier 1” applications focus on “exposomic” pattern recognition for extracting information from multidimensional data sets, whereas second and higher tier applications utilize mechanistic models to develop risk‐relevant exposure metrics for populations and individuals. In this article, “tier 1” applications of TiER explore identification of potentially causative associations among risk factors, for prioritizing further studies, by considering publicly available demographic/socioeconomic, behavioral, and environmental data in relation to two health endpoints (preterm birth and low birth weight). A “tier 2” application develops estimates of pollutant mixture inhalation exposure indices for NCS counties, formulated to support risk characterization for these endpoints. Applications of TiER demonstrate the feasibility of developing risk‐relevant exposure characterizations for pollutants using extant environmental and demographic/socioeconomic data.     

Replication: Revisiting Tversky and Shafir’s (1992) Disjunction Effect with an extension comparing between and within subject designs

Does uncertainty about an outcome influence decisions? The sure-thing principle (Savage, 1954) posits that it should not, but Tversky and Shafir (1992) found that people regularly violate it in hypothetical gambling and vacation decisions, a phenomenon they termed “disjunction effect”. Very close replications and extensions of Tversky and Shafir (1992) were conducted in this paper (N = 890, MTurk). The target article demonstrated the effect using two paradigms in a between-subject design: here, an extension also testing a within-subject design, with design being randomly assigned was added. These results were consistent with the original findings for the “paying to know“ problem (original: Cramer’s V = 0.22, 95% (CI) [0.14, 0.32]; replication: Cramer’s V = 0.30, 95% CI [0.24, 0.37]), yet not for the “choice under risk” problem (original: Cramer’s V = 0.26, 95% CI [0.14, 0.39]; replication: Cramer’s V = 0.11, 95% CI [−0.07, 0.20]). The within-subject extension showed very similar results. Implications for the disjunction effect and judgment and decision-making theory are discussed, and a call for improvements on the statistical understanding of comparisons of between-subject and within-subject designs is introduced. All materials, data, and code are available on https://osf.io/gu58m/.     

Trust and the Dilemmas of Suicide Risk Assessment in Non-government Mental Health Services

Reducing suicide rates is a national mental health priority as over 2,200 people die from suicide each year in Australia. Increasingly, nongovernment organisations (NGOs) provide services to people experiencing severe and persistent mental illnesses—a significant cohort at risk of suicide. While clinical services are generally seen as the arbiters of risk, little is known of how suicide risk assessments are undertaken in NGOs. This article reports the findings of a survey-based pilot study of 44 frontline workers in mental health-focused NGOs in Tasmania, Australia, with the aim of sketching a preliminary picture of this under-studied terrain. We identified the assessment practices utilised by workers, and the challenges and dilemmas they experienced in navigating issues of trust in suicide risk assessment in contexts where they often felt vulnerable and under-prepared. We argue that these early findings demonstrate the need for organisations to foster cultures of trust to facilitate both the activities of relationship building between practitioners and clients, and those of monitoring risk.