Validation of quasi-induced exposure representativeness assumption among young drivers

Objective: Young driver studies have applied quasi-induced exposure (QIE) methods to assess relationships between demographic and behavioral factors and at-fault crash involvement, but QIE's primary assumption of representativeness has not yet been validated among young drivers. Determining whether nonresponsible young drivers in clean (i.e., only one driver is responsible) 2-vehicle crashes are reasonably representative of the general young driving population is an important step toward ensuring valid QIE use in young driver studies. We applied previously established validation methods to conduct the first study, to our knowledge, focused on validating the QIE representativeness assumption in a young driver population.

Methods: We utilized New Jersey's state crash and licensing databases (2008–2012) to examine the representativeness assumption among 17- to 20-year-old nonresponsible drivers involved in clean multivehicle crashes. It has been hypothesized that if not-at-fault drivers in clean 2-vehicle crashes are a true representation of the driving population, it would be expected that nonresponsible drivers in clean 3-or-more-vehicle crashes also represent this same driving population (Jiang and Lyles 2010 Jiang XG, Lyles RW. A review of the validity of the underlying assumptions of quasi-induced exposure. Accid Anal Prev. 2010;42:1352–1358.[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). Thus, we compared distributions of age, gender, and vehicle type among (1) nonresponsible young drivers in clean 2-vehicle crashes and (2) the first nonresponsible young driver in clean crashes involving 3 or more vehicles to (3) all other nonresponsible young drivers in clean crashes involving 3 or more vehicles. Distributions were compared using chi-square tests and conditional logistic regression; analyses were conducted for all young drivers and stratified by license status (intermediate vs. fully licensed drivers), crash location, and time of day of the crash.

Results: There were 41,323 nonresponsible drivers in clean 2-vehicle crashes and 6,464 nonresponsible drivers in clean 3-or-more-vehicle crashes. Overall, we found that the distributions of age, gender, and vehicle type were not statistically significantly different between the 3 groups; in each group, approximately one fourth of drivers were represented in each age from age 17 through 20, half were males, and approximately 80% were driving a car/station wagon/minivan. In general, conclusions held when we evaluated the assumption within intermediate and fully licensed young drivers separately and by crash location and time.

Conclusions: It appears that the representativeness assumption holds among the population of young NJ drivers. We encourage young driver studies utilizing QIE methods to conduct internal validation studies to ensure appropriate application of these methods and we propose utilization of QIE methods to address broader foundational and applied questions in young driver safety.     

The path(s) to employee trust in direct supervisor in nascent and established relationships: A fuzzy set analysis

While many of the propositions advanced by Mayer, Davis, and Schoorman's (1995) integrative model of interpersonal trust have been supported empirically, we still know little about how time impacts the relative importance of the model's elements. In addition, there may be situations in which trust can develop with lesser degrees of any of the trustworthiness facets or propensity to trust. Hence, we apply a configurational set‐theoretic perspective to examine what combinations will be sufficient to produce the presence of trust in a direct supervisor across nascent and established relationships. We find three distinct configurations associated with trust in supervisor, which allows us to elaborate theory and provide novel insights to trust research. In particular, we find that in both nascent and established relationships, perceptions of high supervisor ability, benevolence, and integrity constitute a sufficient configuration for high trust in supervisor. In established relationships, however, there were two paths to high trust in supervisor: (i) perceptions of high supervisor ability and integrity, or (ii) perceptions of high supervisor ability and benevolence, accompanied by high propensity to trust. As such, in established relationships, perceptions of high supervisor benevolence and high propensity to trust may be substitutable with perceptions of high supervisor integrity. Copyright © 2016 John Wiley & Sons, Ltd.     

环境行政处罚的停止执行与放弃执行权

《中华人民共和国行政处罚法》、《中华人民共和国行政诉讼法》、《中华人民共和国行政复议条例》都规定了何种情况下行政处罚停止执行的条款。针对环境行政处罚中存在的放弃执行权，分析种种表现，指出放弃执行权是一种违法行为，必须予以制止，并就停止执行与放弃执行权的区分和行政处罚的全面执行、介入执行、协助执行发表见解。     

A new procedure to optimize the selection of groups in a classification tree: Applications for ecological data

Agglomerative cluster analyses encompass many techniques, which have been widely used in various fields of science. In biology, and specifically ecology, datasets are generally highly variable and may contain outliers, which increase the difficulty to identify the number of clusters. Here we present a new criterion to determine statistically the optimal level of partition in a classification tree. The criterion robustness is tested against perturbated data (outliers) using an observation or variable with values randomly generated. The technique, called Random Simulation Test (RST), is tested on (1) the well-known Iris dataset [Fisher, R.A., 1936. The use of multiple measurements in taxonomic problems. Ann. Eugenic. 7, 179–188], (2) simulated data with predetermined numbers of clusters following Milligan and Cooper [Milligan, G.W., Cooper, M.C., 1985. An examination of procedures for determining the number of clusters in a data set. Psychometrika 50, 159–179] and finally (3) is applied on real copepod communities data previously analyzed in Beaugrand et al. [Beaugrand, G., Ibanez, F., Lindley, J.A., Reid, P.C., 2002. Diversity of calanoid copepods in the North Atlantic and adjacent seas: species associations and biogeography. Mar. Ecol. Prog. Ser. 232, 179–195]. The technique is compared to several standard techniques. RST performed generally better than existing algorithms on simulated data and proved to be especially efficient with highly variable datasets.     

生态旅游对农户家庭收入影响研究——基于倾向得分匹配法的实证分析

参与生态旅游经营已成为保护区周边社区家庭重要的生计,生态旅游经营收入是社区家庭重要的收入来源。本文基于中国7省40个保护区周边社区农户调查数据,研究了家庭参与生态旅游经营对人均纯收入以及人均非农收入的影响,以期能为生态旅游经营的家庭收入效应提供新证据,为缓解保护与发展的矛盾、健全生物多样性保护制度、完善生态旅游发展政策提供实证支撑。研究结果表明:1倾向得分匹配法消除了家庭选择性偏差后,估计出参与生态旅游经营对家庭人均纯收入的收入效应为20%左右,而对人均非农收入的收入效应为47%左右。使用多元线性回归高估了生态旅游经营对家庭人均纯收入的影响,大致高估了8%左右,使用Heckman模型也高估了生态旅游对家庭人均非农收入的影响,大致高估了17%左右。2户主性别、受教育程度、是否为村干部、身体状况、家庭负担比以及耕地面积对农户家庭参与生态旅游经营行为产生显著影响。3结合当前的生态扶贫政策背景,政府以及社会可能高估了生态旅游经营对周边社区家庭收入的影响,追求立竿见影的扶贫效果往往在短期内会获得一定的收效,但是缺乏长期驱动力,最终导致治标不治本的扶贫。因此,政府要合理规划地方生态旅游产业发展,创建一个更有利于社区参与的生态旅游开发模式。一方面,让周边社区家庭参与到生态旅游经营的管理和决策工作中,在生态旅游管理中拥有自主权和决定权;另一方面,建立生态旅游参与的外部约束机制,保障周边社区的利益。     

城镇居民不同收入阶层的基本需求及边际消费倾向研究

扩大城镇居民消费需求是推动我国经济发展方式转变的重要途径。了解城镇居民不同收入阶层的消费特征,有助于制定针对性的激励措施,改善政策的实施效果。本文采用2000-2009年中国城镇居民按收入水平分组的38项消费支出数据,运用改进后的扩展型线性支出模型,对不同收入水平的城镇居民基本需求、边际消费倾向及相关影响因素进行分析。结果显示:中低收入城镇居民的基本需求消费占其可支配收入的较大比重;食品和衣着是其基本需求消费的主要方面;并且在食品、衣着、交通通讯和居住上表现出较大的边际消费倾向。较高收入城镇居民的基本需求支出主要集中于享受型消费;在交通、在外用餐、文化娱乐、文娱用耐用消费品和住房上表现出较大的边际消费倾向。发展和享受型消费品的价格变动对中低收入居民的消费支出影响较大;收入水平的提高有利于城镇居民消费结构的升级。最后,针对不同收入水平的城镇居民,本文提出了刺激消费的差别化政策建议。     

Comments on optimizing the selection of the number of groups in a classification tree

In a recent issue of this journal Guidi et al. (2009) proposed a Random Simulation Test (RST) to assist with the determination of the optimal number of clusters to be extracted from a hierarchical classification tree. This short note illustrates the potential influence that the richness of a simulated new site has on the determination of the optimal level to cut the dendrogram. This is discussed in the context of the need for clear objectives and criteria against which a classification tree can be evaluated. A simple modification of the RST is proposed that the simulated new site of the matrix has an appropriate number of positive entries that lies within the range of the observed matrix. The impact of this modification is then evaluated using an ecological community site-by-species matrix.     

Motorcyclist perception response time in stopping sight distance situations

One of the most effective engineering measures is the provision of an exclusive motorcycle lane that separates motorcycles from other mixed traffic to reduce traffic congestion and motorcycle crashes. Even though the existing exclusive motorcycle lanes in Malaysia reduced the incidents of motorcycle crashes with other vehicles, the design of this special motorcycle lane was based on a cross reference between a bicycle track and a highway. Thus, a suitable design guide is yet to be developed for the geometrical design of a proper and safer exclusive motorcycle lane. Safe stopping sight distance (SSD) has been recognized as a criterion for road design and should be taken into account. Motorcyclist perception response time (PRT) is the time from detection object until the rider reduces motorcycle speed in braking action is an essential component of motorcycle SSD. Two road experiments were conducted to obtain empirical values of motorcycle PRT to expected and unexpected objects. In the expected condition, 89 motorcyclists applied brake as quickly as possible following activation of a light beside the road. In the unexpected condition, 16 riders responded by braking in response to an obstacle that appeared suddenly in their lane. The mean PRT to expected and unexpected object is 0.71 s and 1.25 s respectively. The 85th percentile PRT to unexpected object is 2.12 s. This study found that most riders are capable of responding to an unexpected object along the roadway in 2.5 s or less. Therefore, PRT of 2.5 s is an appropriate value for motorcycle lane geometric design.