The issue of missing data raises concerns in all statistical and educational research. In this study, we focus on missing data in school-based assessment data generated by progressed high school learners (those who did not meet the promotional requirements for their current grades but were allowed to move to the next grade because of policy…

Up to 80% of children with autism spectrum disorder (ASD) experience sleep problems, which have been associated with more severe presentations of ASD symptoms. We examined the bidirectional link between sleep problems and specific ASD symptoms at two time points within 5 years in a well-characterized sample (659 children with ASD). Using…

The aim of this study is to investigate the production and dissemination of mathematical modeling-based projects by gifted students, intended to solve real-life problems, over the four-year Project Production and Management Program (PPMP). The longitudinal research methodology was utilized to examine the project production process among…

Math anxiety (MA) and math performance are generally negatively correlated (Barroso et al., 2021; Namkung et al., 2019). However, the mechanisms underlying this negative association remain unclear. According to the attentional control theory (ACT; Eysenck et al., 2007), anxious individuals experience impaired attentional control during problem…

Developing both conceptual and procedural knowledge is important for students' mathematics competence. This study examined whether U.S. Grade 9 general education mathematics teachers' self-reported use of concept-focused instruction (CFI) and procedure-focused instruction (PFI) were associated differently with ninth graders' algebra achievement…

Despite their many benefits, longitudinal studies are much less common than one-time data collection or pre-post intervention designs. One reason for their scarcity is that longitudinal studies introduce requirements and challenges that non-longitudinal studies do not. One of the biggest challenges is participant attrition. In order to help…

Background: Positive marital relations are crucial for healthy family functioning, whereas conflict-ridden marital relations are linked to children's adjustment problems. According to the Emotional Security Theory, destructive interparental conflict leads to children's emotional insecurity, impacting their adjustment. Objective: This three-wave…

This study explored how caregiver-reported executive functioning domains, assessed by the BRIEF2 at baseline, predicted behavioral challenges reported by caregivers using the CBCL six months later. The sample included 94 youth with Down syndrome, aged 6 to 18 years. Results of hierarchical regression analyses revealed that, after controlling for…

The purpose of this longitudinal study was to examine the development of spelling in a large sample (N = 503, boys: N = 219) of Greek-speaking children with (N = 41) and without (N = 462) reading difficulties. Children were initially tested in Grades 2-4 and then at five consecutive measurement points over a 3-year period, focusing on how initial…

Objective: Children with ADHD often experience functional impairments across various aspects of daily life. This study addresses the dearth of longitudinal research on functional impairment trajectories from preschool to school age in children with symptoms of ADHD and comorbid disorders. Methods: We investigated the extent to which functional…

Imputation or likelihood-based approaches to handle missing data assume the data are missing completely at random (MCAR) or missing at random (MAR). However, little research has examined the missingness pattern before using these imputation/likelihood methods. Three missingness mechanisms -- MCAR, MAR, and not missing at random (NMAR) -- can be…

Longitudinal studies can produce biased estimates of learning if children miss tests. In an application to summer learning, we illustrate how missing test scores can create an illusion of large summer learning gaps when true gaps are close to zero. We demonstrate two methods that reduce bias by exploiting the correlations between missing and…

Researchers, theorists, and practitioners have expressed a renewed interest in the longitudinal dynamics of personality characteristics in adulthood, including organic life span trajectories and their amenability to volitional change. However, this research has apparently not yet expanded to include the Dark Triad (psychopathy, narcissism,…

Dynamic structural equation modeling (DSEM) is a useful technique for analyzing intensive longitudinal data. A challenge of applying DSEM is the missing data problem. The impact of missing data on DSEM, especially on widely applied DSEM such as the two-level vector autoregressive (VAR) cross-lagged models, however, is understudied. To fill the…

Background: Individuals with dementia have communication limitations resulting from cognitive impairments that define the syndrome. Whereas there are numerous cognitive assessments for individuals with dementia, there are far fewer communication assessments. The Profiling Communication Ability in Dementia (P-CAD) was developed to address this gap.…