• Korean Journal of Child Studies
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• v.30 no.4
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• pp.69-85
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• 2009

The purpose of this study was to identify developmental trajectories of externalizing problems in preschoolers and to investigate dimensions of temperament and parental behaviors associated with trajectory groups. Subjects were 180 3- to 5-year-old preschoolers (96 males, 84 females) in the metropolitan area of Seoul. They were assessed three times at 5 month intervals over a one year period. Teachers reported on children's behavior problems, and parents reported on children's temperaments. Latent Growth Curve Modeling Analysis with cohort sequential design revealed externalizing behaviors gradually decreased between 3 and 6. At the 6-year-old level externalizing behaviors were associated with high novelty seeking temperament. The results were discussed in terms of the importance of longitudinal research in developmental psychopathology.

• Journal of Educational Research in Mathematics
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• v.27 no.2
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• pp.207-225
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• 2017

With a significant role of textbooks in shaping students' opportunities to learn, textbook analysis is essential to reveal these opportunities to learn the concept of area and volume. This research aims to show how the Korean textbooks pace students' learning of area and volume across grades by scrutinizing the textbooks with students' developmental sequences, called learning trajectories. Tasks about area and volume in all Korean elementary textbooks (grade 1 to 6) are coded with the specific developmental stages suggested in learning trajectories. As a result, we find considerable misalignment between the textbooks and the learning trajectories. The textbooks provide opportunities to experience developmental progressions of area and volume later than ages suggested in the learning trajectories. In addition, learning opportunities are significantly concentrated in grade 5 for area and grade 6 for volume with heavy emphases on applying formulas of area or volume. The findings from this research provides important implications concerning design of textbooks as well as improving students' opportunities in the mathematics classrooms.

• Journal of Educational Research in Mathematics
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• v.15 no.3
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• pp.353-374
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• 2005

Recently, there have been many changes in researches of mathematics education. There is a growing number of researchers who are interested in empirical researches. According to the these changes, there is also an emphasis on methodology of mathematics education. This means that many researchers try to conduct an research using scientific approach. Therefore, new types of research developing mathematics courses recently has evolved as follows: teaching experiment, hypothetical loaming trajectory, design science, developmental research. The aim of this study is to reflect on developmental research in RME and to induce desirable directions for developing our mathematics courses. In order to attain these purposes, the present paper reflects the philosophy of RME, aim, procedure, data collection, data analysis, and justification of developmental research with illustrating a exemplar Based on these reflections, it is discussed that it needs to construct the mathematics curriculum connecting theory and practice in mathematics education, to report the process of developing mathematics courses faithfully, and to develop real mathematics courses after conducting basic developmental researches in order to take scientific app- roaches for developing mathematics courses.

• Korean Journal of Child Studies
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• v.31 no.6
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• pp.1-13
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• 2010

This study examined the time-dependent effects of changes in private education on the trajectories of academic achievement among early adolescents. Five-wave data was employed from the KYPS; the participants being 2844 (1524 boys, 1320 girls). All were 4th graders in 2004 and became 8th graders in 2008. Latent growth curve model indicated that academic achievement significantly decreased over the five time points, but there were significant individual differences as well. Participants who reported higher initial levels of academic achievement tended to decrease in academic achievement more slowly over time compared to participants who reported lower levels of initial academic achievement. The effects of private education on academic achievement were at their most powerful when participants were in the 4th grade. Private educational experiences among 6th graders had relatively less influence upon the academic achievement of 7th graders.

• Korean Journal of Child Studies
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• v.30 no.3
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• pp.113-125
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• 2009

This study advances knowledge of developmental patterns in poverty and delinquency; data was obtained from waves 1-5 (2003-2007) of the Korea Youth Panel Survey. Semi-parametric group-based modeling (SGM) identified 4 trajectories of poverty from age 13 to 17 : non-poor, poverty increasing, low-level continuous poverty and chronic poverty groups and five developmental trajectories of delinquency : non-offending, late onset, low-level continuous, desisting, and chronic groups. A joint trajectory method predicted patterns of delinquency conditional on poverty trajectories. Chronic and low-level continuous poverty groups were more likely than others to follow chronic trajectories of delinquency; the non-poor group was more likely to be non-offending. Implications of this study for youth welfare were discussed to reduce risk for delinquency.

• Korean Journal of Social Welfare Studies
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• v.45 no.2
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• pp.5-30
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• 2014

This study sought to identify developmental trajectories of bullying victimization from late elementary school through early high school, and to examine internalizing and externalizing problem outcomes associated with the trajectory group membership. Data from Seoul Panel Study of Children were collected annually over a 7-year period from 5th grade of elementary school through 2nd grade of high school (2005~2011). Latent class growth analysis yield three trajectory classes corresponding to stable low (81.2%), stable high (3.5%), and declining bullying victimization (15.6%). Findings from analysis of covariance indicated that students in both stable high and declining trajectory groups reported significantly higher means in internalizing behavior (withdrawal, depression/anxiety, and suicide ideation), compared to those in the stable low group. For externalizing behavior such as aggression and juvenile status offense, students in the stable high group showed higher means, compared to those in the stable low and declining trajectory groups. Developmental pattern of bullying victimization over multiple development stages and associated internalizing and externalizing outcomes are discussed as are the implications for the bullying prevention.

• Journal of the Korean Society of Child Welfare
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• no.54
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• pp.173-197
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• 2016

This study aims to examine developmental trajectories and predictor variables of problem behaviors and school adjustment trajectories among children from low-income families using latent growth modeling. The data was collected from the 2nd year to the 4th year (2012-2014) of a community child center child panel survey conducted by the National Youth Policy Institute. The major findings are as follows. First, as the grade went up, the problem behaviors of children from low-income families increased while school adjustment decreased. Second, multi-level domains, such as individual, school, and family variables influenced school adjustment trajectory, while only individual variables, such as depression, isolation, and motivation for achievement influenced problem behavior trajectory. Third, common protective factors between problem behaviors and school adjustment trajectories were motivation for achievement in and satisfaction of the community child center. Common risk factors between problem behaviors and school adjustment trajectories were isolation and aggression. Based on the results, the implications for child welfare practices were discussed.

• Korean Journal of Child Studies
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• v.37 no.5
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• pp.33-52
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• 2016

Objective: This study aimed to investigate the trajectory of maternal parenting stress during infancy according to the employment status of mothers when each year's depression was controlled and examine the longitudinal effects of parenting stress on affective parenting and socioemotional developmental outcomes for preschoolers. Methods: Using latent growth modeling, the first 4 waves of panel data collected from 2,078 mothers and their babies were analyzed. This nationwide data was provided from the 2008 Panel Study on Korean Children, conducted by the Korea Institute of Child Care and Education. Results: First, maternal parenting stress showed a linear increasing pattern, and there were individual differences in intercept and slope. Second, when each year's maternal depression was controlled, the intercept of parenting stress was lower, but the rate of increase was higher. In multiple group analyses, this increasing pattern of parenting stress was significant only in unemployed mothers. Lastly, the increase of unemployed mothers' parenting stress had direct effects on child emotionality and peer interaction and had an indirect effect on child peer interaction (mediated by affective parenting). Conclusion: The current study verified that the longitudinal effects of increasing parenting stress of unemployed mothers on affective parenting and child socioemotional development when maternal depression level was controlled. These results imply that we need to pay more attention to emotional health and resources of unemployed mothers and provide them with social support as well as employed mothers.

• The Journal of Korean Association of Computer Education
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• v.15 no.3
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• pp.71-80
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• 2012

The purpose of this study is to find out the changing trajectory of online game use as the development of early adolescences. It is also to explore whether the self-control has a current and a lag effect on the game use while development of students. We found these results: (a) There is a statically significant individual variability in initial levels and rates of change in online game use over time. The change of trajectory is declined. (b) Boys also have higher rate of the change in using game than girls over time. (c) Both initial state and changing rate of online game use affects negatively the academic achievement. (d) Current effect always supports, but lag effect does not support except the period from last elementary school grade to middle school grade as explanations for the developmental relation between self-control and online game use in young adolescents.

• Korean Journal of Social Welfare Studies
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• v.49 no.2
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• pp.159-180
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• 2018

The purpose of this study is to identify the trajectories in the use time of children from community children centers and to examine the predictive factors and developmental factors related to each trajectory. The data were derived from the second stage of the Community Children Center Panel Survey using from the first wave (2014) to the third wave (2016). A total of 606 samples were selected from the forth to sixth grades of elementary school. Latent class growth model was employed to identify the trajectories, and the multinominal logistic regression and the logistic regression analysis were used to examine predictive factors and developmental factors. Main results indicated that three types of trajectory were identified: high using group, low using group, and high initial using-rapid declining group. Sex, parental supervision, and use duration were found to be significant predictors. Regarding developmental factors, children who constantly use the community children centers were more likely to increase academic performance and school adaptation. However, no significant results were found for aggression and delinquent behaviors. Based on these findings, this study have suggested the future direction of the community children center.