Rejoinder: Remaining Challenges in Investigating Grade-Retention Effectiveness

This rejoinder, in response to the commentaries of Steiner, Park, and Kim (this issue) and Reshetnyak, Cham, and Hughes (this issue), discusses remaining challenges in grade retention research. First, a same-age comparison assumes that the instruments used in different grades measure ability equally well. We discuss the importance of evaluating the properties of the scaling process to address whether this assumption has been met. Second, we discuss issues in the selection of covariates to be included in the weights. Third, we discuss the unconfoundedness assumption and the problem of remaining imbalance. Finally, we provide an empirical illustration showing that studying grade-retention effectiveness comes with multiple methodological decisions that are rooted in a bias–variance trade-off.     

Using Marginal Structural Modeling for Grade Retention Effects

Vandecandelaere, Vansteelandt, De Fraine, and Van Damme (this issue) described marginal structural modeling (MSM) and used it to estimate the effects of a time-varying intervention, retention (holding back) in school grades, on students' math achievement. This commentary supplements Vandecandelaere et al. (this issue) and discusses several topics in retention studies and MSM. First, we discuss the importance of equating time-varying confounders in retention studies. Second, we discuss same-grade and same-age comparisons in retention studies. Third, we discuss one important section in the authors' overview of MSM: why standard methods (e.g., ANCOVA, propensity score analysis) cannot properly adjust for time-varying confounders. Finally, using the grade retention analyses in Vandecandelaere et al. (this issue) as an example, we provide our insights on four aspects of MSM: (a) covariate selection, (b) estimation of weights, (c) evaluation of balance properties, and (d) missing data handling.     

Examining the efficacy of improved traffic signs and markings at flashing-light-controlled grade crossings based on driving simulation and eye tracking systems

The majority of the collisions at grade crossings occurred at flashing-light-controlled grade crossings. Understanding drivers’ behaviors and visual performances in the process of approaching the crossings is the foundation of improving crossing safety. This study aims at utilizing driving simulation and eye tracking systems to investigate the efficacy of improved traffic signs and pavement markings (PSM) at flashing-light-controlled grade crossings. The improved signs and markings were modeled in a driving simulation system and tested with a series of flashing light trigger time (FLTT) ranging from 2 s to 6 s with 1 s interval increment. Foggy conditions and drivers’ genders and vocations were considered in experiment design. Thirty-six fully-licensed drivers between 30 and 48 years participated in the experiment. Several eye-movement and behavioral measures were adopted as reflections of the subjects’ performances, including the first fixation time on signs and signals and distance to stop line, total fixation duration, compliance rate, stop position, average speed at the stop line, maximum deceleration rate and brake response time. Results showed that compared with traditional grade crossings signs and pavement markings, drivers could perceive signs timelier and fixate on the flashing-light signal earlier in PSM, especially in the scenarios of earlier FLTTs. The improvement in fixation performance and sign design contributed to a higher stop compliance rate. Importantly, it was found that drivers would hesitate to decide whether to stop or cross facing with flashing red lights, which is similar to the dilemma zone of roadway intersections. Drivers were more likely to fall into the dilemma zones when FLTT was <4 s. When FLTT was 2 s, it was particularly difficult to stop in front of the stop line. Moreover, under a foggy condition, drivers had a difficulty in searching signs and had a longer brake response time compared with a clear condition. For the characteristics of drivers, male drivers had longer fixation duration on signs than females. Professional drivers had a higher maximum deceleration rate compared with non-professional drivers. Above findings implied that improved traffic signs and markings would have a potential to improve traffic safety and deserve a field implementation in the future.     

7-10岁学龄儿童ADHD筛查研究

用SDQ（家长版）对上海10所小学二至四年级学生进行测查,以探求被试的ADHD症状表现,锁定ADHD高风险儿童。结果：（1）男生ADHD得分偏高（p<.01）,但女生在红橙两个级别内的百分数均高于男生;（2）9岁被试的ADHD得分分布最分散,占男生ADHD红色级别的比例最大,在女生ADHD得分中均值最大;（3）红橙两个级别为高风险级别。结论：（1）9岁是ADHD症状表现最严重的年龄;（2）女生具有更高的ADHD风险;（3）ADHD高风险被试晒出率：男生14.4%,女生17.4%。     

等级反应多水平侧面模型及其在主观题评分中的应用

探讨了康春花,孙小坚和曾平飞(2016)提出的等级反应多水平侧面模型(GR-MLFM)在包含被试及评分者层面预测变量(完整模型)下的返真性和适用性。结果表明:(1)GR-MLFM完整模型具有逻辑上和数理上的合理性,可用于主观题的评分情境,能较好地检测出评分者效应、影响因素及其影响程度;(2)在数学问题解决的评分实践中,评分员存在两种类型的评分倾向(宽松和严格效应),但绝大多数评分员的宽严度不明显;评分者的责任心可正向预测其严格程度,自信心可正向预测其宽松程度,而情绪稳定性和评分经验的预测作用不显著。     

Defective number module or impaired access? Numerical magnitude processing in first graders with mathematical difficulties

This study examined numerical magnitude processing in first graders with severe and mild forms of mathematical difficulties, children with mathematics learning disabilities (MLD) and children with low achievement (LA) in mathematics, respectively. In total, 20 children with MLD, 21 children with LA, and 41 regular achievers completed a numerical magnitude comparison task and an approximate addition task, which were presented in a symbolic and a nonsymbolic (dot arrays) format. Children with MLD and LA were impaired on tasks that involved the access of numerical magnitude information from symbolic representations, with the LA children showing a less severe performance pattern than children with MLD. They showed no deficits in accessing magnitude from underlying nonsymbolic magnitude representations. Our findings indicate that this performance pattern occurs in children from first grade onward and generalizes beyond numerical magnitude comparison tasks. These findings shed light on the types of intervention that may help children who struggle with learning mathematics.     

时距加工“长度效应”研究述评

所谓长度效应指随着加工长度的变化, 时距加工机制在认知或神经层面会表现出不一致。近20年来, 关于时距加工是否会出现长度效应存在共同机制假设和差异机制假设两种观点。共同机制假设主张不同长度的时距加工认知或神经机制相同, 且该机制可被标量计时模型解释; 而差异机制假设主张不同长度时距加工的认知或神经机制存在差异, 2~3s、1s、1/2s及1/3s等是区别不同机制的分界位置。文章还指出四个值得思考的问题, 即已获证据的可靠性问题、判定标准的多元化问题、分界位置的确定性问题及理论模型的适用性问题。     

中学生攻击性发展特点的研究

本研究以823名中学生为被试,采用问卷法考察了7种类型攻击性的发展特点。结果发现:(1)自行编制的《中学生攻击性问卷》具有较高的信度和效度。(2)在攻击性的各个维度上,攻击性水平均呈现出随年级升高而逐渐增强的发展趋势。(3)在违反制度、言语攻击、身体攻击、恶意和疑心等维度上,男生的攻击性水平显著高于女生。(4)在违反制度和疑心两个维度上,重点校学生的攻击性水平显著高于普通校学生。     

心算形式对不同近似数量系统敏锐度儿童心算表现的影响

选取112名二年级小学生,以点阵比较任务测量近似数量系统敏锐度,同时以工作记忆测验成绩为协变量,探究了不同心算形式（视算、读算）对不同近似数量系统敏锐度儿童心算表现的潜在影响。结果显示：（1）心算形式显著影响心算的正确率,读算形式下儿童的心算表现最好;（2）控制工作记忆影响后,心算形式与近似数量系统敏锐分组均对心算正确率影响显著。总体来讲,读算可能是提高小学儿童简单心算表现的有效形式,并能提高低近似数量系统敏锐度儿童的心算表现。