부동산 양도소득세 정책 효과의 통계적 착시: 주택가격 이중 성분 구조에 따른 희석효과를 중심으로 = Statistical Illusions in the Effects of Real Estate Capital Gains Tax Policies: Focusing on the Dilution Effect Driven by the Dual-Component Structure of Housing Prices

다국어 초록 (Multilingual Abstract)

This study investigates the underlying reasons why previous empirical studies have failed to accurately measure the effects of real estate capital gains tax (CGT) policies in South Korea. In the South Korean housing market, transaction prices are composed of two distinct components: the Jeonse (deposit-based lease) price, representing the use value, and the capital gains price, representing the investment value. When subjected to a CGT shock, the Jeonse price reacts differently from the capital gains price. As these two components combine within the overall transaction price, their respective effects mutually offset and dilute each other, resulting in a “dilution effect” where the overall statistical significance is lost. To verify this statistical illusion, this study proposes a theoretical framework that adapts the space and asset markets of the DiPasquale-Wheaton (D-W) quadrant model to the Korean context, utilizing a ‘Return- Price Vector Model’ to decompose housing prices into the aforementioned two values. Based on this framework, a Synthetic Difference-in-Differences (SDiD) model was constructed using panel data surrounding the August 2nd Real Estate Countermeasures of 2017. The empirical analysis, which employed trading volume, Jeonse price, capital gains price, and overall transaction price as dependent variables, revealed a significant positive (+) effect on the capital gains price and a significant negative (-) effect on both trading volume and Jeonse price. In contrast, no statistically significant policy effect was identified for the overall transaction price. These findings theoretically and empirically suggest that previous studies—which either underestimated or failed to detect the effects of the CGT—did not necessarily prove the policy’s ineffectiveness, but rather exposed the structural limitations of the measurement index. Ultimately, this implies that accurately measuring the impact of real estate tax policies in South Korea requires a sophisticated analytical approach that accounts for the dual-component structure of housing prices.