• Health Policy and Management
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• 제34권1호
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• pp.87-93
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• 2024

Background: In recent years, studies have shown conflicting results regarding the benefits of dietary supplements in reducing healthcare expenditures. This study aimed to address this inconsistency by examining the association between supplement consumption and health expenditures using nationally representative data from the Korea Health Panel Survey (2019-2020). Methods: A 1:1 matched case-control dataset was established using propensity score matching technique based on supplement consumption. Then, total annual healthcare expenditures were compared between the two groups. In addition, a multivariate regression analysis (Proc Surveyreg) was performed to determine the association between the supplement consumption and medical costs. Results: The supplement user group spent about 1.72 million Korean won, while the non-user group spent about 1.43 million Korean won on medical services (p=0.0186). The results of multivariate regression showed that the costs were approximately 26.15% higher in the user group than in the non-user group (p=0.0004). Conclusion: Contrary to the previous studies that have shown the benefits of supplement use in reducing healthcare costs, this study showed that those who consistently consumed supplements spent more on medical services. This can be interpreted in the same context as previous studies suggesting that dietary supplement intake is a healthy behavior for managing one's health. However, we caution against drawing firm conclusions due to data limitations. Further analysis using patient-level epidemiologic data is needed.

• The Korean Journal of Applied Statistics
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• 제35권4호
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• pp.485-499
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• 2022

Controlling the total survey error including sampling error and non-sampling error is very important in sampling design. Non-sampling error caused by non-response accounts for a large proportion of the total survey error. Many studies have been conducted to handle non-response properly. Recently, a lot of non-response imputation methods using machine learning technique and traditional statistical methods have been studied and practically used. Most imputation methods assume MCAR(missing completely at random) or MAR(missing at random) and few studies have been conducted focusing on MNAR (missing not at random) or NN(non-ignorable non-response) which cause bias and reduce the accuracy of imputation. In this study, we propose a non-response imputation method that can be applied to non-ignorable non-response. That is, we propose an imputation method to improve the accuracy of estimation by removing the bias caused by NN. In addition, the superiority of the proposed method is confirmed through small simulation studies.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제11권9호
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• pp.3223-3231
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• 2010

For a long time, most of advanced countries have supported the innovative firms with various support methods such as tax credit, subsidy, human resource education, and so on. Tax credit for innovation is the most popular industrial policy in these countries including Korea. However, in Korea, the effect of tax credit policy has been rarely analyzed. On the other hand, a considerable number of studies discover that tax credit policy in other countries influences positively on invest of R&D expenditure. This paper shows that tax credit policy positively influences on firm's innovation performances in Korea. The evaluated innovative effect of tax credit policy in this paper is more persuasive because it introduces various innovation performance variables including patent application with Propensity score matching method(PSM).

• Journal of the Korea Computer Graphics Society
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• 제23권5호
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• pp.51-56
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• 2017

In this paper, we define "presence" as a physiological and emotional feeling which feels that he or she is immerged in a specific artworks when he/she is very interested in the artwork. To measure the presence, we use a combined approach of subjective survey and brain signals (EEG). Subjective survey includes PQS (presence questionnaire survey) and IDQS (individual differences questionnaire survey). We experimented with 30 random populations, and we performed Cronbach's ${\alpha}$ test to verify the validity of the survey results. We also cross-checked the survey with EEG test for the populations. From our experimentation, we conclude that opponent color (e.g. yellow and blue) makes strong excitation on presence. In this paper, we believe that there are strong presence even in the abstract images, and it can be stronger than photo-realistic images if we well-design color, forms on the artwork.

• Health Policy and Management
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• 제34권1호
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• pp.68-77
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• 2024

Background: Depressive disorders can be categorized into daily depression and clinical depression. The experience of depressive disorder can increase health care utilization due to decreased treatment compliance and somatization. On the other hand, the clinical depression group may also experience social prejudice associated with the illness, which can limit their access to health care utilization. In terms of the significance of health care utilization as a factor in individual and social issues, this study aims to compare the health care utilization of the clinical depression group with that of the non-depressed group and the daily depression group. Methods: The analysis utilized the inverse probability of treatment weighting based on the generalized propensity score. Results: As a result of the analysis, clinical depression and daily depression were higher among women, low-income groups, individuals with low education levels, and so forth. The clinical depression group was also higher among individuals who were not economically active, did not have private health insurance, or had multiple chronic diseases. The number of outpatient department visits in the depression group was significantly higher than in the non-depressed group. In addition, the number of outpatient department visits for the clinical depression group was significantly higher than that for the daily depression group. Outpatient medical expenses were higher in the depression group than in the non-depressed group, and there was no significant difference between the clinical depression group and the daily depression group. Conclusion: Health care utilization was higher in the depression group than the non-depressed group, it was also higher in the clinical depression group than the daily depression group.