Conditional Direction Dependence Analysis: Evaluating the Causal Direction of Effects in Linear Models with Interaction Terms

Abstract

Direction dependence analysis (DDA) makes use of higher than second moment information of variables (x and y) to detect potential confounding and to probe the causal direction of linear variable relations (i.e., whether x?→?y or y?→?x better approximates the underlying causal mechanism). The “true” predictor is assumed to be a continuous nonnormal exogenous variable. Existing methods compatible with DDA, however, are of limited use when the relation of a focal predictor and an outcome is affected by a moderator. This study presents a conditional direction dependence analysis (CDDA) framework which enables researchers to evaluate the causal direction of conditional regression effects. Monte–Carlo simulations were used to evaluate two different moderation scenarios: Study 1 evaluates the performance of CDDA tests when a moderator affects the strength of the causal effect x?→?y. Study 2 evaluates cases in which the causal direction itself (x?→?y vs y?→?x) depends on moderator values. Study 3 evaluates the robustness of DDA tests in the presence of functional model misspecifications. Results suggest that significance tests compatible with CDDA are suitable in both moderation scenarios, i.e., CDDA allows one to discern regions of a moderator in which the causal direction is uniquely identifiable. An empirical example is provided to illustrate the approach.     

The influence of chemical cues on the territorial prior residence effect in convict cichlids (cichlasoma nigrofasciatum Günther)

The importance of accumulated chemical cues on the occurrence of the territorial prior residence effect was investigated in two experiments using adult convict cichlids (Cichlasonul nigrofasciatum). In the first experiment, pairs of fish, matched on a number of criteria, were randomly assigned to three independent treatment conditions in which (1) the territorial marker (pot or clump of plants) was removed just prior to a direct encounter in the aquarium of the resident (pair member in whose aquarium the encounter took place) with accumulated chemical cues remaining intact; (2) the marker was removed, as well as the chemical cues; or (3) the marker was present, but the chemical cues were removed. Results showed that a significant prior residence effect occurred when the marker was present, but did not occur in either condition in which the marker was removed. A second experiment, in which the marker was removed and the gravel substrate altered, also did not reveal a signficant prior residence effect. Apparently, the territorial resident recognizes his territory by using certain visual cues, with accumulated chemical cues being neither necessary nor sufficient in this process.     

Property rights and genetic engineering: Developing nations at risk

Eighty percent of (commercial) genetically engineered seeds (GES) are designed only to resist herbicides. Letting farmers use more chemicals, they cut labor costs. But developing nations say GES cause food shortages, unemployment, resistant weeds, and extinction of native cultivars when “volunteers” drift nearby. While GES patents are reasonable, this paper argues many patent policies are not. The paper surveys GE technology, outlines John Locke’s classic account of property rights, and argues that current patent policies must be revised to take account of Lockean ethical constraints. After answering a key objection, it provides concrete suggestions for implementing its ethical conclusions.     

高中学生解决计算类化学问题的表征及其与策略关系的研究

在国内外关于问题解决中表征和策略研究的基础上,本研究提出了高中学生解决计算类化学问题的五个表征层次和四种解决策略,并用出声思维法对15位典型被试学生进行了详尽的个案分析.研究结果表明:高中学生在解决计算类化学问题时的表征程度(包括表征时间的长短和表征正确率的高低)决定了其问题解决策略的选取,表征程度高的学生倾向于选择相对优化的策略.     

Context,content, and relativism

This paper argues against relativism, focusing on relativism based on the semantics of predicates of personal taste. It presents and defends a contextualist semantics for these predicates, derived from current work on gradable adjectives. It then considers metasemantic questions about the kinds of contextual parameters this semantics requires. It argues they are not metasemantically different from those in other gradable adjectives, and that contextual parameters of this sort are widespread in natural language. Furthermore, this paper shows that if such parameters are rejected, it leads to an unacceptably rampant form of relativism, that relativizes truth to an open-ended list of parameters.

The ontology of intentionality I: the dependence ontological account of order: mediate and immediate moments and pieces of dependent and independent objects

This is the first of three essays which use Edmund Husserl's dependence ontology to formulate a non-Diodorean and non-Kantian temporal semantics for two-valued, first-order predicate modal languages suitable for expressing ontologies of experience (like physics and cognitive science). This essay's primary desideratum is to formulate an adequate dependence-ontological account of order. To do so it uses primitive (proper) part and (weak) foundation relations to formulate seven axioms and 28 definitions as a basis for Husserl's dependence ontological theory of relating moments. The essay distinguishes between dependence v. independence, pieces v. moments, mediate v. immediate pieces and moments, maximal v. non-maximal pieces, founded v. unfounded qualities, integrative v. disintegrative dependence, and defines the concepts of the completion of an object, the adumbrational equivalence relation of objects, moments of unity which unify objects, and relating moments which relate objects. The eight theorems [CUT90]-[CUT97] show that relating moments of unity provide an adequate account of order in terms of primitive (proper) part and (weak) foundation relations.     

Comparing score tests and other local dependence diagnostics for the graded response model

Score tests for identifying locally dependent item pairs have been proposed for binary item response models. In this article, both the bifactor and the threshold shift score tests are generalized to the graded response model. For the bifactor test, the generalization is straightforward; it adds one secondary dimension associated only with one pair of items. For the threshold shift test, however, multiple generalizations are possible: in particular, conditional, uniform, and linear shift tests are discussed in this article. Simulation studies show that all of the score tests have accurate Type I error rates given large enough samples, although their small‐sample behaviour is not as good as that of Pearson's Χ² and M₂ as proposed in other studies for the purpose of local dependence (LD) detection. All score tests have the highest power to detect the LD which is consistent with their parametric form, and in this case they are uniformly more powerful than Χ² and M₂; even wrongly specified score tests are more powerful than Χ² and M₂ in most conditions. An example using empirical data is provided for illustration.     

尿沉渣法、干化学法及传统镜检测定尿液中有形成分的对比研究

以传统镜检法结果作为标准,分别采用AX4280全自动尿液干化学法分析仪（干化学法）和IQ200尿沉渣分析仪（尿沉渣法）及两种方法的并联和串联检测新疆石河子地区532例患者的清洁中段尿,并评价两种方法的检测效果。结果显示,与传统镜检法比较,干化学法和尿沉渣法串联对尿液中红、白细胞检出率的阳性预测值高,具有临床意义;尿沉渣法对红、白细胞检测误诊率较高,需用镜检进行确认。尿沉渣法和干化学法可对临床提供一定的依据,但不能完全代替传统镜检,几种方法可作为互补,提高检测准确性。     

题组反应理论及其在中学英语考试中的应用研究

题组作为众多测验中的一种常见题型,由于项目间存在一定程度的依赖性而违背了局部独立性假设,若用项目反应模型进行参数估计将会出现较大的偏差.题组反应理论将被试与题组的交互作用纳入到模型中,解决了项目间相依性的问题.笔者对题组反应理论的发展、基本原理及其相关研究进行了综述,并将其应用在中学英语考试中.与项目反应理论相对比,结果发现：（1）题组反应模型与项目反应模型在各参数估计值的相关系数较强,尤其是能力参数和难度参数;（2）在置信区间宽度的比较上,题组反应模型在各个参数上均窄于项目反应模型,即题组反应模型的估计精度优于项目反应模型.     

Guidance systems across Europe: heritage,change and the art of becoming

Guidance systems exist within learning, working and welfare cultures, which are upheld by prevailing institutions and stakeholders. Implementing a lifelong approach questions rooted codes and idiosyncrasies of the sectors across which guidance is distributed. To support individuals' careers, unlock their potential and increase their contribution to the economy i.e. support their process of becoming, lifelong guidance must strive for effective systems' integration across policy fields, cultures and organisations. This article departs from national experiences and discusses how cultures and institutional contexts generate resistance to change, but can also be the departure point for the successful development of lifelong support to people's careers.