Health data is among the most sensitive personal information, and its secondary use for research, policy, and analytics hinges on one question: how can the data be used without exposing the individuals behind it? In the late 2010s, Korea was expanding its ambitions for health big data and cross-agency linkage but lacked a dedicated, health-specific standard for de-identification. From 2017 to 2020, Junghwan Park led the drafting of Korea's first health-information de-identification guideline to fill that gap.
The guideline's job is to define, for the health context, what de-identification means, which techniques apply, and what process an institution must follow before health data is used or shared. It has to be technically sound enough to genuinely protect privacy and practical enough for hospitals, agencies, and researchers to apply consistently — and it must sit within Korea's broader Personal Information Protection Act, whose framework governs the use of pseudonymized data for research and statistical purposes.
That foundational work has since matured into the Ministry of Health and Welfare's Healthcare Data Utilization Guideline (보건의료데이터 활용 가이드라인), a living document maintained by the ministry's Healthcare Data Promotion Division and revised as law and practice evolve — most recently in a December 2025 revision. Where Park's original guideline established the methodology, the current version carries it forward as the operative reference for de-identifying and using health data across the system.
The de-identification guideline and the national medical big-data linkage platform Park worked on in the same years are two sides of the same effort: the platform made cross-agency linkage technically possible, while the guideline made it legally and ethically defensible. Together they helped establish that Korea could pursue health big data and precision medicine without abandoning privacy protection — a balance that remains at the center of the country's health-data policy.