Blinder-Oaxaca Decomposition of Changes in Korean Medicine Utilization: Evidence from Korea Health Panel Survey 2009 and 2018

Objectives: This paper examines the changes in the utilization rates of Korean Medicine (KM) outpatient clinics from 2009 to 2018. It also explores the factors influencing these changes across three age groups (0-17, 18-64, 65 and over) using logit-based Blinder-Oaxaca decomposition.Methods: The author utilizes data from the Korea Health Panel Survey (KHPS) for the years 2009 and 2018. They perform a Blinder-Oaxaca decomposition analysis using logistic regression, modeling outpatient visits as the dependent variable within Andersen’s healthcare utilization framework, which encompasses predisposing, enabling, and need factors. The analysis breaks down outpatient utilization differences into structural characteristics (Endowments Effect, EE), changes in variable effects (Coefficients Effect, CE), and the interaction between these factors (Interaction Effect, IE).Results: The utilization rate of KM institutions increases among those aged 18-64 and those aged 65 and over; however, it drops significantly among those aged 0-17. In the 18-64 age group, the increase is mainly due to the IE between population structure and variable effects. In contrast, in the 65 and over age group, changes in variable effects are the primary factor. Unlike the other two groups, the decline among the 0-17 age group cannot be fully explained by observable factors alone, implying that external or unmeasured influences might be involved.Conclusions: Age-specific differences in the use of KM underscore the need for a more comprehensive understanding of the factors that influence these patterns.