Fraction arithmetic facility is fundamental to learning more advanced math topics. However, attaining the ability to add and subtract fractions is hard for many students. The present longitudinal study examined students' growth on simple addition and subtraction word problems between fourth and sixth grades (N = 536). Latent class growth analyses…

Within the context of the Direct and Indirect Effects Model of Writing (Kim & Park, 2019), we examined a dynamic relations hypothesis, which contends that the relations of component skills, including reading comprehension, to written composition vary as a function of dimensions of written composition. Specifically, we investigated: (1) whether…

A data-driven, transdiagnostic approach was used to identify the cognitive dimensions linked with learning in a mixed group of 805 children aged 5 to 18 years recognized as having problems in attention, learning, and memory by a health or education practitioner. Assessments included phonological processing; information processing speed; short-term…

We investigated the dimensionality of various indicators of reading prosody, and the relations of word reading and listening comprehension to the identified dimension(s) of reading prosody, using longitudinal data from Grades 1 to 3. A total of 371 English-speaking children were assessed on oral text reading, word reading, and listening…

Difficulties in mathematics are argued to stem from impairments of a specialized system of numerical magnitude representation. This study investigates whether different measures of numerical magnitude understanding in kindergarten uniquely predict mathematical achievement concurrently and 6 months later, and also examines the relative explanatory…

Identifying meaningful cognitive and noncognitive predictors of mathematical competence is critical for developing targeted interventions for students struggling with mathematics. Here, 317 students' short-term verbal memory, verbal and visuospatial working memory, complexspatial abilities, intelligence, and mathematics attitudes and anxiety were…

The present longitudinal study investigated the developmental trajectories of addition, subtraction, and multiplication fluency; their relationships to general cognitive functions; and potential interrelations between reading fluency and growth in arithmetic fluency for different operations. The central prediction was that measures of arithmetic…

We investigated 2 hypotheses of a recently proposed integrative theoretical model of reading, the direct and indirect effects model of reading (DIER; Kim, 2017b, 2019): (a) hierarchical relations and (b) dynamic relations (or differential relations) of skills to reading comprehension. Students were assessed on reading comprehension, word reading,…

West Syndrome is a severe, early-onset epilepsy syndrome, with significant implications for subsequent neurological and cognitive development. While most children with a prior diagnosis of West Syndrome initially follow a normal developmental trajectory, there is evidence of subsequent emergence of clusters of difficulties, including autism…

We examined the direction of the relation between morphological awareness and reading/spelling skills in 2 languages varying in orthographic consistency (English and Greek) and whether word reading fluency and vocabulary mediate the relation between morphological awareness and reading comprehension. One-hundred and 59 English-speaking Canadian and…

Sex differences in the strength of the relations between mathematics anxiety, mathematics attitudes, and mathematics achievement were assessed concurrently in sixth grade (n = 1,091, 545 boys) and longitudinally from sixth to seventh grade (n = 190, 97 boys). Mathematics anxiety was composed of two facets, one associated with evaluations and the…

Background: Writing involves multiple processes, drawing on a number of language, cognitive, and print-related skills, and knowledge. According to the Direct and Indirect Effects model of Writing (DIEW; Kim & Park, 2019, "Reading and Writing," 32, 1319), these multiple factors have hierarchical, interactive, and dynamic relations.…

Dysgraphia, a specific learning disability, impairs legible and automatic letter production by hand, which can interfere with written composing. The goal of the current study was not to investigate effective methods for teaching self-regulated writing to students with dysgraphia, but rather to investigate their self that is involved in their…

The importance of fraction knowledge to later mathematics achievement, along with U.S. students' poor knowledge of fraction concepts and procedures, has prompted research on the development of fraction learning. In the present study, participants' (N = 536) development of fraction magnitude understanding and fraction arithmetic skills was assessed…

The contributions of domain-general abilities and domain-specific knowledge to subsequent mathematics achievement were longitudinally assessed (n = 167) through 8th grade. First grade intelligence and working memory and prior grade reading achievement indexed domain-general effects, and domain-specific effects were indexed by prior grade…