Revisiting the Model Size Effect in Structural Equation Modeling

Fitting a large structural equation modeling (SEM) model with moderate to small sample sizes results in an inflated Type I error rate for the likelihood ratio test statistic under the chi-square reference distribution, known as the model size effect. In this article, we show that the number of observed variables (p) and the number of free parameters (q) have unique effects on the Type I error rate of the likelihood ratio test statistic. In addition, the effects of p and q cannot be fully explained using degrees of freedom (df). We also evaluated the performance of 4 correctional methods for the model size effect, including Bartlett’s (1950), Swain’s (1975), and Yuan’s (2005) corrected statistics, and Yuan, Tian, and Yanagihara’s (2015) empirically corrected statistic. We found that Yuan et al.’s (2015) empirically corrected statistic generally yields the best performance in controlling the Type I error rate when fitting large SEM models.     

在线学习的理论与实践

本刊今年第3期刊登了记者对国际知名远程教育专家、加拿大阿萨巴斯卡大学特里·安德森教授的专访。安德森教授在专访中提及他和同事法希·埃劳米的新著《在线学习的理论与实践》,“希望能得到我们中国朋友的青睐和欣赏”。该书收录了16篇论文,作者全部是阿萨巴斯卡大学的教师和研究者,也都是20世纪90年代中期以来阿萨巴斯卡大学为了应对日益裁减的政府资助和生源的锐减而进行大规模教育改革的实践者和见证人,这些论文既有经验总结又有前瞻性的思考,对我国的远程教育事业不无借鉴价值。鉴于此,本刊特邀肖俊洪先生谨将该书两位主编所撰写的“引言”中的有关全书内容概要的部分译成中文,以飨读者。     

State-mandated accountability as a constraint on teaching and learning science

The purpose of this study is to examine the effect of state-mandated policy, emphasizing control through performance-based instruction and student test scores as the basis for determining school accreditation, on the teaching and learning of science. The intended consequence of instigating the rational theory of management by one state is to improve their current level of student literacy. However, some contend that the implementation of the policy has results that are not intended. The identification of the tension between the intended and unintended results of centralized policy making is the basis for examining a specific case in which the rational model is implemented. One hundred and sixty-five seventh-grade science students and four teachers are participants in the study. Qualitative analysis is the research methodology used as a means to provide detailed information about the contextual nature of the classroom processes. The intention is to identify and describe features of the behavior setting that influence the behavior of the teachers and their students. Three assertions generated during the field work were: Teachers redefine the goals of science instruction as the acquisition of facts and isolated skills, teachers alter their usual instructional behavior to implement uniform instructional procedures, and the teacher/student classroom interaction constrains students' opportunities to learn science. The implications of the study indicate that the state-mandated policy has results that are in opposition to the intended results. Instead of improving the practices of teachers, the implementation of the policy constrains and routinizes the teachers' behavior, causing them to violate their own standards of good teaching. They feel pressured to “get through” the materials so students will score well on tests. The classroom interaction is structured in such a way as to inhibit students from asking questions of their own. As a result, students' opportunity to express curiosity and inquiry—central processes in scientific thinking—are constrained. These unintended consequences of the implemented state policy, instead of improving science teaching and learning, continue to reduce science instruction to the literal comprehension of isolated facts and skills.     

Dialect variation,dialect-shifting,and reading comprehension in second grade

The purpose of this study was to examine second graders’ (n = 680) changing spoken nonmainstream American English (NMAE) use in relation to their oral language and reading comprehension achievement. Fall NMAE production was negatively associated with fall achievement scores. NMAE production generally decreased from fall to spring. Students who qualified for the US Free and Reduced Lunch program (FARL) and who had stronger language skills were more likely to decrease their NMAE use (i.e., dialect shifting) than their peers who did not qualify for FARL or their peers with weaker language skills. Dialect shifting for a sub-sample of 102 students who used substantial amounts of NMAE at the beginning of the school year was predicted by school context, controlling for reading and language skills—in general, students who attended more affluent schools dialect shifted to a greater extent than did their peers who attended higher poverty schools. Greater dialect shifting in this group predicted gains in reading comprehension from fall to spring.     

Achieving equivalence: a transnational curriculum design framework

Transnational education is now essential to university international development strategies. As a result, tertiary educators are expected to engage with the complexities of diverse cultural contexts, different delivery modes, and mixed student cohorts to design quality learning experiences for all. To support this transition we developed a transnational curriculum design framework that synthesises knowledge about what impacts on curriculum design. This framework aims to help academic developers communicate complex educational concepts and foster international communities of practice. It guides cyclical implementation that is focused on achieving equivalent and quality educational outcomes for students regardless of their location across the globe.     

Conditioning of the nictitating membrane response of the rabbit (Oryctolagus cuniculus) as a function of length and degree of variation of intertrial interval

The study involved three experiments. The first, a parametric investigation of nictitating membrane conditioning with eight constant intertrial intervals (ITIs) between 5 and 120 sec, orthogonal to interstimulus intervals (ISIs) of 250 and 750 msec plus three temporal conditioning control groups, revealed that performance improved rapidly with increasing ITI but stabilized at relatively low ITI values. At 750-msec ISI, a decrement in performance was found at 60-sec ITI. Experiment II, using constant ITIs of 45–75 sec in 5-sec steps, at 750-msec ISI confirmed the trend toward a performance decrement around 60 sec, although the trend was weak and highly variable. Experiment III evaluated the differences in performance between constant and variable ITI, using three ITI values and three conditions of variation at each value. Findings were discussed in terms of differences in conditioning resulting from both length and degree of variation of ITI and some subtle effects which may emerge only when constant ITIs are used.