Investigating Efficacy,Moderators and Mediators for an Online Mathematics Homework Intervention

Abstract

We report on a randomized controlled trial of an intervention that leverages the availability of laptops for all public-school students in the state of Maine. The intervention, called “ASSISTments,” provides feedback to students as they solve mathematics homework problems and automatically prepares reports for teachers about student performance on daily assignments. Teachers received training and coaching on formative assessment. Data was collected from 43 schools, 87 teachers, and 2769 7th grade students. Planned analyses describe use of the intervention, analyze the impact of the intervention on an end-of-year standardized assessment, and explore variables that may moderate or mediate impacts. Findings indicate that students in the schools assigned to use ASSISTments learned more and the impact was greater for students with lower prior mathematics achievement. Although evidence shows that teachers used the intervention to target instruction to students’ needs, the mediating role of this practice was unclear. We also examined the generalizability of the findings and found generalizability to be limited due to the setting in Maine. Implications for policy, practice, and future research are discussed.     

A Multiple-Design,Experimental Strategy: Academic Probation Warning Letter's Impact on Student Achievement

Abstract

We aimed to compare the findings of three research designs to bracket effect estimates of a strongly worded warning letter delivered by certified mail to students on academic probation.

We embedded an experiment within a regression discontinuity design and calculated two achievement estimates, average GPA and percentage of students remaining on probation. Study participants attended a large Midwestern college. Cohen's d experimental effect size was .45. Regression discontinuity design results were validated by our experimental evidence, and outcome measures were generally statistically significant. We provided additional supportive evidence using comparative RD control group design logic. Regression point displacement design results were successfully replicated using a within-study comparison inside the experiment. In the context of probation, a diverse design, replicative approach provided considerable promise for more precise estimation of intervention effectiveness. We found no deleterious impact on reenrollment and concluded that the certified letter represents an inexpensive probation policy.     

An Experiment to Evaluate the Efficacy of Cognitive Tutor Geometry

Abstract

This randomized, controlled field trial estimated the causal impact of a technology-based geometry curriculum on students’ geometry achievement, as well as their attitudes toward mathematics and technology. The curriculum combines learner-centered classroom pedagogy with individualized, computer-based student instruction. Conducted over a 3-year period in eight high schools within an urban fringe district, the study found that students assigned to the treatment curriculum scored 19% of a standard deviation lower on the geometry posttest than their counterparts assigned to the district's standard curriculum, but found no statistically significant impact on students’ attitudes toward mathematics and technology. Researchers also collected observation and interview data on teachers’ instructional practices. These data suggest that many teachers had difficulty implementing the treatment curriculum's learner-centered pedagogy. In fact, observed levels of learner-centered practices were only modestly higher in treatment classes than in control classes. In both treatment and control classes, however, higher levels of learner-centered pedagogy were associated with higher student achievement in geometry.     

Scaling Up the Implementation of a Pre-Kindergarten Mathematics Curriculum: Teaching for Understanding With Trajectories and Technologies

Abstract

This study used a randomized field trial design to evaluate the efficacy of a research-based model for scaling up an intervention focused on preschool mathematics. Although the successes of research-based educational practices have been documented, equally well known is the paucity of successful efforts to bring these practices to scale. The same research corpus provides guidelines to scale up successful interventions. We designed an intervention model based on that research, including mathematics curricula with an emphasis on teaching for understanding following developmental guidelines, or learning trajectories, and using technology at multiple levels. We then implemented that model and evaluated the implementation with a limited scale up study. Within a design involving 25 classrooms serving children at risk for later school failure, we examined the impact of the model, using measures of fidelity of implementation, classroom observations of mathematics environment and teaching, and child outcomes. High levels of fidelity of implementation resulted in consistently higher scores in the intervention, compared to control, classes on the observation instrument and significantly and substantially greater gains in children's mathematics achievement in the intervention, compared to the control, children (effect size = .62).     

A Randomized Experiment of a Cognitive Strategies Approach to Text-Based Analytical Writing for Mainstreamed Latino English Language Learners in Grades 6 to 12

Abstract

This study reports Year 1 findings from a multisite cluster randomized controlled trial of a cognitive strategies approach to teaching text-based analytical writing for mainstreamed Latino English language learners (ELLs) in 9 middle schools and 6 high schools. There were 103 English teachers stratified by school and grade and then randomly assigned to the Pathway Project professional development intervention or control group. The Pathway Project trains teachers to use a pretest on-demand writing assessment to improve text-based analytical writing instruction for mainstreamed Latino ELLs who are able to participate in regular English classes. The intervention draws on well-documented instructional frameworks for teaching mainstreamed ELLs. Such frameworks emphasize the merits of a cognitive strategies approach that supports these learners’ English language development. Pathway teachers participated in 46 hrs of training and learned how to apply cognitive strategies by using an on-demand writing assessment to help students understand, interpret, and write analytical essays about literature. Multilevel models revealed significant effects on an on-demand writing assessment (d = .35) and the California Standards Test in English language arts (d = .07).     

Estimating the Standard Error of the Impact Estimator in Individually Randomized Trials With Clustering

ABSTRACT

In the “individually randomized group treatment” (IRGT) experimental design, individuals are first randomly assigned to a treatment arm or a control arm, but then within each arm, are grouped together (e.g., within classrooms/schools, through shared case managers, in group therapy sessions, through shared doctors, etc.) to receive services. In the common setting where the second-stage grouping is not experimentally controlled, we demonstrate that the standard error estimators for the estimated treatment effects from both random and fixed effects models are biased because parameters required to compute the standard errors are not identifiable from the data. We discuss implications for designing and analyzing IRGTs and provide suggestions for mitigating the bias.     

一种面向随机调度无线传感器网络的路由方法

休眠机制是无线传感器网络中节省能量、提高网络寿命的主要方法之一,但同时也带来了端到端延迟性能的下降.尤其对于低占空比无线传感器网络,不同路由方法对网络性能特别是延迟性能的影响很大.提出一种基于随机调度的分布式逐跳路由方法:根据邻居节点的位置信息及其随机调度种子信息,在下一跳选择中以前进距离与延迟之比作为转发测度.理论分析和仿真结果显示,对比已有方法,该方法在端到端分组投递延迟和转发跳数方面具有优势.     

Assessing child maltreatment prevention via administrative data systems: A case example of reproducibility

Critical issues about scientific reproducibility have been raised about biomedical research, including the reliability of data and analyses within a given study. The case example in this article examined a reproducibility issue pertaining to the use of administrative data systems for evaluation of child maltreatment (CM) prevention, making use of a prevention study conducted over a decade ago that provided a unique opportunity. The place-randomization study, which randomized counties to condition, found that community-wide implementation of a parenting and family support intervention produced positive impact on county-wide rates for substantiated CM cases and out-of-home placements, documented through a state information system. The key consideration is whether and to what extent the administrative record data re-examined retroactively a decade later for the original study’s time period would yield comparable results to those based on data acquired at the time of the study. The results indicated that despite small changes over time, the same data patterns and statistical effects were reproducible for the two archival outcome variables. For substantiated CM, the reproduced analyses reflected higher effect sizes and a clear pattern of reduction as a function of intervention. For out-of-home placements, effect sizes were quite comparable to the original ones, reflecting preventive impact. Overall, this case study illustrated the verifiability of data reproducibility in the context of a population outcome evaluation, which underscores the importance of reliable population-prevalence measurement as an essential part of a comprehensive public health strategy aimed at the prevention of CM.     

我国医学期刊遵循临床试验注册制度的现状调查

临床试验注册的目的是减少临床试验报告的偏倚,提高研究的透明度和科学性。本研究调查了我国258种医学核心期刊的稿约,57种(22.1%)期刊稿约中要求遵循临床试验注册制度,其中50种期刊提出了具体的著录要求。进一步深入探讨各期刊发表的随机对照试验(RCT)中临床试验注册号著录格式及内容的一致性和准确性,以及RCT撰写遵循CONSORT报告指南是否对著录注册号有影响。本研究结果表明目前我国医学期刊对临床试验注册和报告指南的遵循情况并不理想,报告注册的RCT仅占17.2%,仍存在对注册制度重视不足及执行不严格等问题,而期刊要求遵循CONSORT声明可能对RCT的注册有积极的影响。建议医学期刊遵循临床试验注册制度,提高对其的正确认识和重视,这需要期刊审稿人、编辑及作者的共同参与,通过提高临床试验注册的比例,进而提升研究的透明度。