구조적 측정오차를 고려한 준모수적 Fay-Herriot 모형

류수락(Soorack Ryu),황진섭(Jinseub Hwang) 한국자료분석학회 2018 Journal of the Korean Data Analysis Society Vol.20 No.1

대부분의 연구에서는 측정을 통하여 변수를 생성하게 되며, 이러한 변수들 중에는 측정오차를 가지고 있는 경우가 발생할 수 있다. 이러한 측정오차는 통계적 분석을 복잡하게 하며 이러한 문제를 일반적으로 측정오차 문제라고 한다. 또한 현재의 과학적인 현상들은 단순한 선형적 관계가 아닌 복잡한 관련성을 증명하고자 하고 있으며, 이를 해결하기 위한 여러 가지 비선형적 모형들이 개발되고 있다. 이에 사전 연구(Ryu, Hwang, 2017)에서는 측정오차를 가지는 공변량의 참값(true value)에 대한 비확률성(non-stochastic)을 가정하는 기능적 측정오차모형(functional measurement error model)과 비선형성을 고려한 준모수적 Fay-Herriot 모형을 제안하였다. 본 연구에서는 이를 확장하여 측정오차를 가지는 공변량의 참값에 확률성(stochastic)을 가정하는 구조적 측정오차모형(structural measurement error model)을 고려한 준모수적 Fay-Herriot 모형을 제안하고자 한다. 모형 적합 및 모수 추정에서는 MCMC(Markov chain Monte Carlo) 방법을 사용하는 계층적 베이지안 모형을 고려하였다. 두 가지의 비선형적 함수를 이용한 모의실험을 통하여 본 연구에서 제안한 모형의 우수성을 확인하였으며, 실증자료의 적용을 위해 국민건강영양조사의 제7기 1차연도(2016) 자료를 사용하였다. In most studies, variables are created through measurement and some of these variables may have measurement errors. This measurements error complicates the statistical analysis and this problem is commonly called measurement error problem. Also, current scientific phenomena are trying to demonstrate the complexity of relationships, not a simple linear relationships and then various nonlinear models are being developed. In our previous study (Ryu, Hwang, 2017) we proposed a semiparametric Fay-Herriot model under the functional measurement error that assumes a non-stochastic true value of the covariate. In this study, we propose a semiparametric Fay-Herriot model under structural measurement error that assumes a stochastic true value of the covariate as an extension of our previous model. For the model fitting and parameter estimation, we consider hierarchical Bayesian model approach using Markov chain Monte Carlo method. To check the superiority of the proposed model, we conduct simulation studies using two nonlinear functions and we use the seventh KNHANES (Korean national health and nutrition examination survey) data for the application.

결과변수와 공변량의 측정 오차를 고려한 Fay-Herriot 모형

류수락(Soorack Ryu),황진섭(Jinseub Hwang) 한국자료분석학회 2020 Journal of the Korean Data Analysis Society Vol.22 No.1

소지역의 효율적인 추정을 위해 Fay-Herriot 모형의 다양한 확장 버전이 제안되었다. 그러나 대부분의 사전 연구에서는 공변량(covariate)에만 측정오차를 고려하였으며 결과변수(outcome variable)의 측정오차(measurement error)는 고려하지 않고 있다. 이에 본 연구에서는 결과변수와 공변량의 측정오차모형을 반영한 확장된 Fay-Herriot 모형을 제안하고자 한다. 측정오차를 가지는 결과변수의 참값(true value)에 비확률성(non-stochastic)을 가정한 기능적 측정오차모형(functional measurement error model)과 측정오차를 가지는 공변량의 참값에 확률성(stochastic)을 가정한 구조적 측정오차모형(structural measurement error model)을 고려하였다. 모형 적합과 모수 추정을 위해 MCMC(Markov chain Monte Carlo) 방법의 계층적 베이지안 모형을 사용하였다. 본 연구에서 제안하는 모형의 우수성을 확인하기 위해 모의실험과 실증자료 분석을 수행하였으며, Arima et al.(2015)에서 사용한 선형적 함수와 2010 이탈리아 가계 예산 조사(2010 Italian household budget survey) 자료를 사용하였다. 모의실험과 실증자료 분석을 통해 본 연구에서 제안하는 모형의 성능이 더 우수하였다. Various extension versions for Fay-Herriot model have been proposed for efficient small area estimation. However, most previous studies have considered only covariate of measurement error model even though the outcome variable may also have measurement error model. In this paper, we propose an extended Fay-Herriot model that can reflect the measurement error model of outcome variable and covariate. We consider a measurement error model of the outcome variable and covariate. To fit the model and estimate parameters, we consider hierarchical Bayesian model approach based on Markov chain Monte Carlo method. To check the superiority of the proposed model, we use one linear function in simulation studies and we use the 2010 Italian household budget survey data for the empirical study. The results for simulation studies and the empirical study show that the proposed model has the better performance than the error model considering measurement error of covariate only.

성향점수 분석방법에 따른 대구광역시 학생들의 교과목별 사교육 효과

류수락(Soorack Ryu),황진섭(Jinseub Hwang) 한국데이터정보과학회 2019 한국데이터정보과학회지 Vol.30 No.4

대구시 학생들의 사교육 효과에 대한 많은 기존 연구들이 있지만 대부분의 연구들은 표본설계를 통해 수집된 대표성 있는 자료가 아니고 결과들을 일반화할 수 없는 한계점을 가지고 있다. 이에 본 연구에서는 대구광역시교육연구정보원에서 표본설계를 통해 학생, 학부모, 교사를 대상으로 설문을 진행한 2016년 대구교육실태조사 자료를 기반으로 대상자들의 교란요인을 보정하고자 성향점수의 여러가지 분석방법(매칭, 공변량보정, 역확률가중치)을 활용하여 초중고 학생들의 교과목별 (국어, 수학, 영어) 사교육 참여 여부에 따른 학업성취도와 수업이해도, 전국연합학력평가 효과를 확인하고자 한다. 최종 연구대상자는 초등학생 410명, 중학생 571명, 고등학생 913명이었으며 연구 결과를 살펴보면, 초등학생에서는 역확률 가중치 방법을 적용하는 경우 수학에서 학업성취도와 수업이해도에 대한 유의한 사교육효과가 나타났다. 중학생에서는 매칭 방법을 적용한 경우 수학과 영어의 수업이해도, 역확률 가중치 방법을 적용한 경우 국어의 수업이해도를 제외하고 모두 유의한 효과가 나타났다. 고등학생에서는 매칭 방법을 적용한 경우 영어의 학업성취도를 제외하고 모두 유의한 효과가 나타났으며, 역확률 가중치 방법을 적용한 경우 국어와 수학의 학업성취도와 전국연합학력평가, 공변량 보정방법을 적용한 경우 수학의 학업성취도에 유의한 효과가 나타났다. 이와 같이 성향점수의 분석방법에 따라 학력별 및 교과목별 사교육의 효과는 일부 다르게 나타나고 있으므로 분석방법의 특징을 고려하여 연구목적에 적합한 성향점수 방법의 선택이 필요하다. In this study we use the 2016 educational survey data of Daegu Educational Research and Information Institute and we confirm the effect of private tutoring for elementary, middle and high school students in Daegu about the academic achievement, learning understanding and national mock test based on propensity score (matching, covariate adjusting and IPTW (inverse probability of treatment weighting)). According to the results, in elementary school, there are significant effects for the academic achievement and learning understanding of Math when using IPTW. In middle school, it is an effective for the learning understanding of Math and English when using matching, and in all except for the learning understanding of Korean based on IPTW. In high school, all except the academic achievement of English have significant effect when using matching and there are significant effects for the academic achievement and national mock test in Korean and Math, and the academic achievement in Math based on IPTW and covariate adjusting, respectively. The effectiveness of a private tutoring by grade and subject is different according to the method, so it is necessary to select the propensity score method appropriate for the research purpose considering the characteristics of methods.

Assessment of Parenting Attitudes by Children and Adolescents with Migraine

Kyeong Mi Lee(Kyeong Mi Lee),Min Suk Koh(Min Suk Koh),Ho-chan Lim(Ho-chan Lim),Soorack Ryu(Soorack Ryu),Yong Joo Kim(Yong Joo Kim),Jin-Hwa Moon(Jin-Hwa Moon) 대한소아신경학회 2022 대한소아신경학회지 Vol.30 No.4

Purpose: We aimed to investigate the parenting attitudes reported by patients and their relationships with the characteristics of headaches in children and adolescents with migraine. Methods: We conducted a retrospective review of medical records of children and adolescents with migrainous headaches (n=115; 59.1% female; mean age, 11.89±2.00 years). Children evaluated parental attitudes using the Parenting Attitude Test-Youth (PAT-Y), which comprises eight subscales and four newly devised secondary subscales. Headache severity was calculated by the visual analog scale (VAS), monthly frequency (MF), and VAS×MF/4 (VF). The scores of PAT-Y subscales and the correlations between PAT-Y scores and headache severity were analyzed by age group and sex. Scores for children’s depression inventory, childhood behavior checklists, and an attention deficit hyperactivity disorder scale were also analyzed. Results: In the elementary school age group, VAS was weakly negatively correlated with the “achievement press” (r=-0.28, P<0.05) and “high expectation” (r=-0.25, P<0.05) attitudes, and VF was weakly negatively correlated with “achievement press” (r=-0.32, P<0.05), “punishment” (r=-0.27, P<0.05), and “high expectation” (r=-0.29, P<0.05). In the middle-school age group, MF and VF were moderately positively correlated with the “achievement press” attitude (r=0.48, P<0.01 and r=0.48, P<0.01, respectively), VF was weakly positively correlated with the “neglectful” attitude(r=0.31, P<0.05), and MF was weakly positively correlated with scores for depression (r=0.29, P<0.05) and internalized problems (r=0.31, P<0.05). Conclusion: Parenting attitudes perceived by children and adolescents with migrainous headaches varied by age, and some parenting attitudes were related to headache severity. Education on age-appropriate parenting attitudes may help cope with migrainous headaches.

Anti-reflux Surgery Versus Proton Pump Inhibitors for Severe Gastroesophageal Reflux Disease: A Cost-Effectiveness Study in Korea

( Susan Park ),( Sungsoo Park ),( Joong-min Park ),( Soorack Ryu ),( Jinseub Hwang ),( Jin-won Kwon ),( Kyung Won Seo ) 대한소화기기능성질환·운동학회(구 대한소화관운동학회) 2020 Journal of Neurogastroenterology and Motility (JNM Vol.26 No.2

Background/Aims The economic burden for gastroesophageal reflux disease (GERD) has recently increased in Asian countries. This study investigates the cost-effectiveness between anti-reflux surgery and medication, with proton pump inhibitors (PPIs) for GERD in Korea. Methods We used a decision tree and Markov model to obtain the costs and quality-adjusted life years (QALYs) of the surgical and medical strategies. Our target cohort was the severe GERD patients aged 50 years old who required a continuous double dose of PPIs. The time horizon was 10 years and all estimates were discounted at 5% per year. The incremental cost-effectiveness ratio of the anti-reflux surgery compared with medication with PPIs was calculated. Sensitivity analyses were performed on all relevant variables. Results The cost-utility analysis indicated anti-reflux surgery was more cost-effective than medication among severe GERD patients over a 10- year period. The model predicted that the surgical strategy had a cost savings of $551 and the QALYs had a gain of 1.18 as compared with the medical strategy. The break-even point in costs of the anti-reflux surgery over the medication was estimated to be 9 years. Sensitivity analyses using the varying parameter assumptions demonstrated the robustness of the study results. Conclusions This study showed anti-reflux surgery was less expensive and more effective therapy over the PPI medication after 9 years of follow-up. This suggests the surgical strategy is a cost-effective alternative to PPI medication among patients who need long-term management for GERD in Korea. (J Neurogastroenterol Motil 2020;26:215-223)

Social Inequalities of Oral Anticoagulation after the Introduction of Non-Vitamin K Antagonists in Patients with Atrial Fibrillation

유희태,Pil-Sung Yang,Jinseub Hwang,Soorack Ryu,Eunsun Jang,김태훈,엄재선,김종윤,박희남,이문형,Gregory Y.H. Lip,정보영 대한심장학회 2020 Korean Circulation Journal Vol.50 No.3

Background and Objectives: Nationwide social inequalities of oral anticoagulation (OAC) usage after the introduction of non-vitamin K antagonist oral anticoagulants (NOACs) have not been well identified in patients with atrial fibrillation (AF). This study assessed overall rate and social inequalities of OAC usage after the introduction of NOAC in Korea. Methods: Between January 2002 and December 2016, we identified 888,540 patients with AF in the Korea National Health Insurance system database. The change of OAC rate in different medical systems after the introduction of NOAC were evaluated. Results: In all population, overall OAC use increased from 13.2% to 23.4% (p for trend <0.001), and NOAC use increased from 0% to 14.6% (p for trend <0.001). Compared with pre-reimbursement (0.48%), the annual increase of OAC use was significantly higher after partial (1.16%, p<0.001), and full reimbursement of OAC (3.72%, p<0.001). Full reimbursement of NOAC (adjusted odds ratio, 2.10; 95% confidence interval, 2.04–2.15) was independently associated with higher OAC use. However, the difference of overall OAC usage between tertiary referral hospitals and nursing or public health centers increased from 17.9% in 2010 to 36.8% in 2016. Moreover, usage rate of NOAC was significantly different among different medical systems from 37.2% at the tertiary referral hospital and 5.5% at nursing or public health centers. Conclusions: Introduction of NOACs in routine practice for stroke prevention in AF was associated with improved rates of overall OAC use. However, significant practice-level variations in OAC and NOAC use remain producing social inequalities of OAC despite full reimbursement.

지역아동센터 이용 아동과 주 양육자의 지역사회 환경에 대한 인식이 아동의 신체활동에 미치는 영향

박지영(Park, Jiyoung),김완수(Kim, Wansoo),김수빈(Kim, Soobin),류수락(Ryu, Soorack),전희정(Jeon, Heejeong) 한국보건간호학회 2018 韓國保健看護學會誌 Vol.32 No.3