Spatial Concentration of Housing Completions in Korea, 2005–2025: HHI, CR3 and Sensitivity Analysis

Overview This dataset examines the spatial concentration of housing completions across South Korea's 17 administrative regions from 2005 to 2025, using official housing construction completion statistics published by the Ministry of Land, Infrastructure and Transport (MOLIT). The study provides 357 region-year observations covering 21 years and calculates annual regional concentration measures, including the Herfindahl–Hirschman Index (HHI) and the concentration ratio of the three largest regions (CR3). Methods The analysis includes: Annual HHI and CR3 calculations based on regional housing completion shares. A regional decomposition of the change in HHI between 2014 and 2018. Sensitivity analysis combining Sejong and Chungnam into a single geographic unit. Sensitivity analysis excluding Gyeonggi Province and recalculating the concentration of the remaining regions. Reproducibility checks of regional totals, annual indicators, and derived calculations. Key Findings National HHI reached its highest observed value in 2018, approximately 0.17434, whereas CR3 reached its maximum in 2021, approximately 57.94%. Gyeonggi Province accounted for more than 100% of the net increase in national HHI between 2014 and 2018, because changes in other regions partially offset its positive contribution. Combining Sejong and Chungnam preserves 2018 as the highest-HHI year. Excluding Gyeonggi changes the highest-HHI year to 2011. Data and Reproducibility The deposited package contains derived annual indicators, a region-year panel, regional HHI decomposition results, variable definitions, reproducibility code, documentation, and file integrity checksums. The underlying MOLIT source workbook is not redistributed in the package and can be obtained separately from the official statistical catalog. Source: https://stat.molit.go.kr/portal/cate/statMetaView.do?hRsId=468 Scope and Limitations The dataset covers housing completions across all residential housing categories, not apartments alone. Results are descriptive and should not be interpreted as causal effects, evidence of housing shortages, or population-adjusted housing supply. Historical administrative boundary changes, particularly the establishment of Sejong, and retrospective revisions to official statistics may affect long-run comparisons. This dataset is an independently calculated derivative of official statistical data and is not an official MOLIT publication.