Jun Young Park, Sang Gyu Lee
In February 2024, approximately 90% of resident physicians in Republic of Korea (= South Korea) collectively resigned from training hospitals in protest of the government's plan to reform healthcare system, creating an abrupt and nationwide supply shock in the physician workforce. Using publicly available Health Insurance Review and Assessment Service data across eight timepoints (December 2022-March 2026), we describe how this shock reshaped the distribution of general physicians-licensed physicians without specialty board certification-across institution types, regions, urban-rural areas, and clinic specialties. Between December 2023 and December 2024, trainees at training hospitals declined from 13,001 to 1,208 (-90.7%), while general physicians at non-training institutions rose from 5,557 to 9,157 (+64.8%). The increase was concentrated in urban areas, capital-area clinics, and a small set of specialties dominated by dermatology, internal medicine, and aesthetic-related fields; per-population rates confirmed that Gangwon showed the smallest reallocation. Trainee numbers partially recovered by March 2026. Approximately 8,200 (≈ 69%) of the displaced trainees were not accounted for by the concurrent rise in general physicians at non-training institutions. This study is descriptive and does not itself perform causal inference; rather, it documents how a sudden physician supply expansion was absorbed by the existing healthcare market and provides an empirical foundation for future causal analyses treating this shock as a natural experiment.