Reliability formulas for noncompleted or speeded tests

New formulas are developed to give lower bounds to the reliability of a test, whether or not all respondents attempt all items. The formulas apply in particular, then, to completed tests, pure speed tests, pure power tests, and any mixture of speed and power. For the case of completed tests, the formulas give the same answer as certain standard ones; for noncompleted tests the formulas give a correct answer where previous standard formulas are inappropriate. The formulas hold both in the sense of retest reliability and of parallel tests.This research was facilitated by an uncommitted grant-in-aid to the writer from the Behavioral Sciences Division of the Ford Foundation.     

Examining regional variability in work ethic within Mexico: Individual difference or shared value

Despite the acceptance of work ethic as an important individual difference, little research has examined the extent to which work ethic may reflect shared environmental or socio‐economic factors. This research addresses this concern by examining the influence of geographic proximity on the work ethic experienced by 254 employees from Mexico, working in 11 different cities in the Northern, Central and Southern regions of the country. Using a sequence of complementary analyses to assess the main source of variance on seven dimensions of work ethic, our results indicate that work ethic is most appropriately considered at the individual level.     

Controlling variability

In human motor control, there is uncertainty in both estimation of initial sensory state and prediction of the outcome of motor commands. With practice, increasing precision can often be achieved, but such precision incurs costs in time, effort, and neural resources. Therefore, motor planning must account for variability, uncertainty, and noise, not just at the endpoint of movement but throughout the movement. The author presents a mathematical basis for understanding the time course of uncertainty during movement. He shows that it is possible to achieve accurate control of the endpoint of a movement even with highly inaccurate and variable controllers. The results provide a first step toward a theory of optimal control for variable, uncertain, and noisy systems that must nevertheless accomplish real-world tasks reliably.     

Cognitive variability

Children's thinking is highly variable at every level of analysis, from neural and associative levels to the level of strategies, theories, and other aspects of high-level cognition. This variability exists within people as well as between them; individual children often rely on different strategies or representations on closely related problems presented close in time. Recognizing such variability can help us both describe development more accurately and better explain how cognitive change occurs.     

The storm and stress (or calm) of early adolescent self-concepts: within- and between-subjects variability

This study uses intraindividual variability and change methods to test theoretical accounts of self-concept and its change across time and context and to test the developmental implications of this variability. The 5-year longitudinal study of 541 youths in a rural Pennsylvania community from 3rd through 7th grade included twice-yearly assessments of self-concept (academic and social), corresponding external evaluations of competence (e.g., teacher-rated academic skills, peer-nominated "likeability"), and multiple measures of youths' overall adjustment. Multiphase growth models replicate previous research, suggesting significant decline in academic self-concept during middle school but modest growth in social self-concept from 3rd through 7th grade. Next, a new contribution is made to the literature by quantifying the amount of within-subject variability (i.e., "lability") around these linear self-concept trajectories as a between-subjects characteristic. Self-concept lability was found to associate with a general profile of poorer competence and adjustment and to predict poorer academic and social competence at the end of 7th grade above and beyond level of self-concept. Finally, there was substantial evidence that wave-to-wave changes in youths' self-concepts correspond to teacher and peer evaluations of youths' competence, that attention to peer feedback may be particularly strong during middle school, and that these relations may be moderated by between-subjects indicators of youths' general adjustment. Overall, findings highlight the utility of methods sensitive to within-subject variation for clarifying the dynamics of youths' self-system development.     

Beyond positive or negative: variability in daily parent-adolescent interaction quality is associated with adolescent emotion dysregulation

Previous work on the contribution of family environments to adolescent emotion dysregulation has tended to focus on broad parenting characteristics (such as warmth); however, it is possible that day-to-day variability in parenting may also relate to emotion dysregulation. The current study sought to test whether inconsistency in the quality of daily parent-youth interactions related to multiple indices of emotion dysregulation in adolescents. Two-hundred-twenty-two adolescents (ages 13–16; 53% female) participated with one parent. Adolescents completed 14-days of diary reporting on the quality of interactions with their parent (negative/neutral/positive) and their emotion dysregulation experiences for each day. Analyses reveal that, beyond the effects of average interaction quality, adolescents with greater variability in the quality of their interactions with their parent reported greater average emotion dysregulation across the days of diary recording and demonstrated greater variability in their ratings of daily emotion dysregulation. Findings were not accounted for by parental warmth or hostility, parent-reported trait-level emotion regulation, or day-level associations between study variables. In these ways, greater variability – and not merely greater negativity – during interactions between parents and adolescents was related to adolescent emotion dysregulation, suggesting that consistency in parent–adolescent relationships may be an important dimension of psychosocial risk to consider within families.     

A scoping review of non-linear analysis approaches measuring variability in gait due to lower body injury or dysfunction

ObjectivesThe aim of this review is to evaluate and summarize existing literature using non-linear analysis methodology to consider variability of human movement due to lower limb injury or dysfunction.DesignScoping review.MethodsAn electronic keyword search was performed on three databases to identify appropriate research. This research was then examined for details of measures and methodology, use of control groups and general study characteristics to identify related themes.ResultsFifteen papers were reviewed and synthesized. A range of conditions were studied, mainly affecting knee and ankle joints, and each using different non-linear methods and different equipment (motion capture, accelerometry, and muscle activation) to evaluate the mathematically chaotic nature of the movement and assess the variability in gait. Sample sizes and effect sizes are commonly small in these studies.ConclusionsNon-linear analysis is a potentially useful tool in both diagnosis and evaluation of injury, and this should inform future clinical processes when dealing with injury and movement variability. Despite numerous studies evaluating neurological conditions and ageing, focus on injury is limited, with notable gaps in terms of considering other joints and joint actions, so this should be a promising area of research to develop our understanding of injury and rehabilitation and how this affects gait variability.     

信度的再认识与信度概括化研究

本文首先对信度概念进行了明确,指出信度是评价测验结果可靠与否的一个指标,而不是测验工具的不变属性。针对测验结果的信度估计的可变性,介绍了上世纪末Vacha-Haase提出的信度概括化研究方法．即一种用来探索得分信度估计的可变性、并对引起变异的预测源进行探讨的一种元分析方法。最后通过对信度概括化研究手段的分析,指出信度概念的再认识与信度概括化研究将会给心理测验工作者带来新的启示。     

Effects of practice on variability, effects of variability on transfer

Five experiments examined how practice early in skill acquisition affected variability and accuracy during skill retention (Experiments 1-5) and skill transfer (Experiments 3, 4, 5). Lag constraints required that each path from apex to base of a computer-generated pyramid display differ from some number (the lag) of immediately prior paths. Location constraints specified end points at which paths must exit the pyramid. In all experiments, an early optimal period for acquiring a variability level was identified. Both low and high levels of variability were sustained during retention; high levels facilitated transfer. The results suggest that (a) early practice that requires high variability sensitizes learners to changes in condition and (b) such perception-performance links facilitate transfer by activating appropriate alternative strategies/schema or initiating their construction.     

测验信度估计：从α系数到内部一致性信度

沿用经典的测验信度定义, 简介了信度与a 系数的关系以及a系数的局限。为了推荐替代a系数的信度估计方法, 深入讨论了与a 系数关系密切的同质性信度和内部一致性信度。在很一般的条件下, 证明了a 系数和同质性信度都不超过内部一致性信度, 后者不超过测验信度, 说明内部一致性信度比较接近测验信度。总结出一个测验信度分析流程, 说明什么情况下a 系数还有参考价值; 什么情况下a 系数不再适用, 应当使用内部一致性信度(文献上也常称为合成信度)。提供了计算同质性信度和内部一致性信度的计算程序, 一般的应用工作者可以直接套用。     

Bilingual corpus callosum variability

Magnetic resonance imaging was used to produce midsagittal images of the corpus callosum of 19 right-handed adult male and female subjects. The preliminary findings of this study indicate that significant adaptation in the anterior midbody of the corpus callosum has occurred to accommodate multiple language capacity in bilingual individuals compared to monolingual individuals. The main interpretation of this finding is that the precentral gyrus is involved in bilingual faculty adaptation assuming a role consistent with the somatotopical input to areas dedicated to the mouth, and input to association tracts connecting the premotor and supplementary motor cortices. This paper discusses possible implications to neuroscientists, second language educators, and their students.     

Reinforcing saccadic amplitude variability

Saccadic endpoint variability is often viewed as the outcome of neural noise occurring during sensorimotor processing. However, part of this variability might result from operant learning. We tested this hypothesis by reinforcing dispersions of saccadic amplitude distributions, while maintaining constant their medians. In a first experiment we reinforced the least frequent saccadic amplitudes to increase variability, and then reinforced the central part of the amplitude distributions to reduce variability. The target was placed at a constant distance from the fovea after the saccade to maintain the postsaccadic visual signal constant and an auditory reinforcement was delivered depending on saccadic amplitude. The second experiment tested the effects of the contingency. We reinforced high levels of variability in 4 participants, whereas 4 other participants were assigned to a yoked control group. On average, saccadic amplitude standard deviations were doubled while the medians remained mostly unchanged in the experimental participants in both experiments, and variability returned to baseline level when low variability was reinforced. In the control group no consistent changes in amplitude distributions were observed. These results, showing that variability can be reinforced, challenge the idea of a stochastic neural noise. We instead propose that selection processes constrain saccadic amplitude distributions.