• Communications for Statistical Applications and Methods
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• v.24 no.3
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• pp.255-269
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• 2017

This article explores the analysis of longitudinal surveys in which same units are investigated on several occasions. Multivariate exponential ratio type estimator has been proposed for the estimation of the finite population median at the current occasion in two occasion longitudinal surveys. Information on several additional auxiliary variables, which are stable over time and readily available on both the occasions, has been utilized. Properties of the proposed multivariate estimator, including the optimum replacement strategy, are presented. The proposed multivariate estimator is compared with the sample median estimator when there is no matching from a previous occasion and with the exponential ratio type estimator in successive sampling when information is available on only one additional auxiliary variable. The merits of the proposed estimator are justified by empirical interpretations and validated by a simulation study with the help of some natural populations.

• Journal of Korean Clinical Nursing Research
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• v.22 no.3
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• pp.359-367
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• 2016

Purpose: The purpose of this study was to examine the effects of physical, psychological, and social factors on the health status of patients undergoing hemodialysis using longitudinal data. Methods: Two surveys were conducted within a period of two-year. A total of 75 patients participated in both surveys. Eight variables including symptoms, treatment belief, hope, meaning-focused coping, family support, friend/peer support, healthcare provider support, and health status were measured. Data were analyzed by paired t-test, Pearson's correlation coefficients, and hierarchical multiple regressions. Results: The mean age of the participants was 47.31 and the average duration of dialysis was 8.27 years. There was no difference in scores on perceived health status between the two year-interval surveys. The two-year follow-up on perceived health status was correlated with baseline perceived health status, friend/peer support, meaning-focused coping, hope, and symptoms. As the result of the regression analysis, friends/peer support (${\beta}=.31$, p=.013) and baseline perceived health status (${\beta}=.30$, p=.020) were found to be significant predictors of subsequent health status which explained 39.0% of the variance. Conclusion: This study suggests the importance of psychosocial resources for positive health outcomes in patients with a chronic illness. Nursing interventions aimed to provide renal peer support need to be developed and tested.

• Korean Medical Education Review
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• v.24 no.2
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• pp.156-171
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• 2022

The purpose of this study was to establish a model for constructing longitudinal data for medical school, and to structure cohort and longitudinal data using data from Yonsei University College of Medicine (YUCM) according to the established input-environment-output (I-E-O) model. The study was conducted according to the following procedure. First, the data that YUCM has collected was reviewed through data analysis and interviews with the person in charge of each questionnaire. Second, the opinions of experts on the validity of the I-E-O model were collected through the first expert consultation, and as a result, a model was established for each stage of medical education based on the I-E-O model. Finally, in order to further materialize and refine the previously established model for each stage of medical education, secondary expert consultation was conducted. As a result, the survey areas and time period for collecting longitudinal data were organized according to the model for each stage of medical education, and an example of the YUCM cohort constructed according to the established model for each stage of medical education was presented. The results derived from this study constitute a basic step toward building data from universities in longitudinal form, and if longitudinal data are actually constructed through this method, they could be used as an important basis for determining major policies or reorganizing the curricula of universities. These research results have implications in terms of the management and utilization of existing survey data, the composition of cohorts, and longitudinal studies for many medical schools that are conducting surveys in various areas targeting students, such as lecture evaluation and satisfaction surveys.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.26 no.5
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• pp.239-248
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• 2023

Purpose: The parents of adolescents with inflammatory bowel disease may experience impaired mental health and quality of life. This longitudinal study aimed to verify whether the mental health and quality of life of the parents of adolescents with inflammatory bowel disease declined when their children had active disease. Methods: Sociodemographic data, parental anxiety, depression, and quality of life were analyzed using validated questionnaires for each variable. After the baseline survey, the second and follow-up surveys were conducted at 3 and 12 months, respectively. The active disease group comprised eight parents whose children had active disease during the baseline and second surveys. The remission group comprised 14 parents whose children remained in remission during both surveys. The improved group comprised nine parents whose children experienced active disease at baseline and remission during the second survey. Parental mental health and quality of life were compared among the groups. Results: Significantly higher levels of anxiety were observed in the active disease group in all surveys (p<0.050). Although depression levels and quality of life did not differ significantly among the three groups, pairing the active disease group with other groups showed some large effect sizes. Conclusion: Parents tended to experience decreased mental health and quality of life when their adolescents experienced active inflammatory bowel disease. Consequently, our hypothesis was partially verified. Therefore, parents need support when their children have active disease; this finding highlights the need for parental support systems.

• Korean Journal of Culture and Social Issue
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• v.20 no.4
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• pp.329-346
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• 2014

Current study examine whether happiness (life satisfaction, positive affect, and negative affect) improves academic achievement (GPA) by longitudinal data. Two surveys were conducted with one year interval and total 112 respondents participated in both surveys. Hierarchical regression analysis was employed to investigate that happiness in the first time have an effect on GPA in the second time after controlling for GPA in the first time as well as demographic variables. We found that life satisfaction and positive affect in the first survey improved GPA after the next semester. Interestingly, GPA did not bring happiness by this longitudinal data. The implication for study were discussed.

• International Journal of Computer Science & Network Security
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• v.21 no.4
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• pp.52-58
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• 2021

Questionnaires and surveys are increasingly being used to collect information from participants of empirical software engineering studies. Usually, such data is analyzed using statistical methods to show an overall picture of participants' agreement or disagreement. In general, the whole survey population is considered as one group with some methods to extract varieties. Sometimes, there are different opinions in the same group, but they are not well discovered. In some cases of the analysis, the population may be divided into subgroups according to some data. The opinions of different segments of the population may be the same. Even though the existing approach can capture the general trends, there is a risk that the opinions of different sub-groups are lost. The problem becomes more complex in longitudinal studies where minority opinions might fade over time. Longitudinal survey data may include several interesting patterns that can be extracted using a clustering process. It can discover new information and give attention to different opinions. We suggest using a data mining approach to finding the diversity among the different groups in longitudinal studies. Our study shows that diversity can be revealed and tracked over time using the clustering approach, and the minorities have an opportunity to be heard.

• International Journal of Computer Science & Network Security
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• v.24 no.3
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• pp.201-210
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• 2024

In empirical software engineering research, there is an increased use of questionnaires and surveys to collect information from practitioners. Typically, such data is then analyzed based on overall, descriptive statistics. Overall, they consider the whole survey population as a single group with some sampling techniques to extract varieties. In some cases, the population is also partitioned into sub-groups based on some background information. However, this does not reveal opinion diversity properly as similar opinions can exist in different segments of the population, whereas people within the same group might have different opinions. Even though existing approach can capture the general trends there is a risk that the opinions of different sub-groups are lost. The problem becomes more complex in case of longitudinal studies where minority opinions might fade or resolute over time. Survey based longitudinal data may have some potential patterns which can be extracted through a clustering process. It may reveal new information and attract attention to alternative perspectives. We suggest using a data mining approach to finding the diversity among the different groups in longitudinal studies (agile skeptics). In our study, we show that diversity can be revealed and tracked over time with the use of clustering approach, and the minorities have an opportunity to be heard.

• Survey Research
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• v.7 no.2
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• pp.71-95
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• 2006

This article presents strengths of Computer-Assisted Personal Interviewing(CAPI) in social surveys with complicated questionnaires, from examples of a pilot and the first year surveys of the Korean Longitudinal Study of Ageing(KLoSA). This study focuses on how to improve the quality of data by using CAPI and finds five strengths among others. First of all, CAPI can contribute to reducing response errors by structuring the logic and path of questionnaires, setting a response range, and maintaining response consistency. Second, CAPI enhances convenience of interviewing by allowing customized questions and automatic calculation and scoring. It also allows the 'help' function. Third, its random arrangement of questions prevents response order effect and/or questions order effect. Fourth, CAPI can raise the response rate by reducing item non-responses. Fifth, it makes it easy monitoring interviewing, thus helps supervising interviewers and modifying questionnaires when necessary. These merits of CAPI contribute to reducing possible errors in the process of interviewing, therefore improve the data quality.

• Survey Research
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• v.11 no.1
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• pp.1-18
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• 2010

We compare various imputation methods for compensating wave nonresponse that are commonly adopted in many panel surveys. Unlike the cross-sectional survey, the panel survey is involved a time-effect in nonresponse in a sense that nonresponse may happen for some but not all waves. Thus, responses in neighboring waves can be used as powerful predictors for imputing wave nonresponse such as in longitudinal regression imputation, carry-over imputation, nearest neighborhood regression imputation and row-column imputation method. For comparison, we carry out a simulation study on a few income data from the Korean Welfare Panel Study based on two performance criteria: predictive accuracy and estimation accuracy. Our simulation shows that the ratio and row-column imputation methods are much more effective in terms of both criteria. Regression, longitudinal regression and carry-over imputation methods performed better in predictive accuracy, but less in estimation accuracy. On the other hand, nearest neighborhood, nearest neighbor regression and hot-deck imputation show higher performance in estimation accuracy but lower predictive accuracy. Finally, the mean imputation shows much lower performance in both criteria.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.7
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• pp.3029-3033
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• 2014

Background: Dynamic changes of cancer-related fatigue (CRF) among hospitalized patients with colorectal cancer were determined. Materials and Methods: This longitudinal, descriptive study involved 96 hospitalized patients with colorectal cancer, all recruited from a tertiary general hospital in Guangzhou, China. Patients completed questionnaires three times to assess the degree of fatigue, and measurement points were within one week of admission, at 2 to 3 days after surgery and 3 weeks after surgery. Results: Significant differences among the three measurement points (p<0.01) were observed. The scores of fatigue in the second survey were the highest, followed by the third and first surveys. Colon cancer patient scores were higher than those of rectal cancer patients with a significant difference (p<0.05). Colorectal patients experienced different degrees of fatigue at different periods during hospitalization. Conclusions: This study highlights the importance of interventions that are carefully tailored to patients based on the characteristics at different periods to alleviate fatigue.