Allocative inefficiency in physician workforce distribution: specialty-level NHI-covered reimbursement analysis in...

About 52 million residents are insured under the single-payer National Health Insurance (NHI) of South Korea. Twenty-six board-certified clinical specialties practice under this system, yet specialty-level matching between physician manpower and NHI-financed workload has not been reported.

This study is an ecological cross-sectional analysis using specialty (n = 26) as the unit of observation. For 2023 and 2024, annual NHI reimbursement per specialty was divided by the mean specialist headcount to yield per-specialist reimbursement. This indicator captures facility-level resource use rather than physician effort in isolation. Specialties were placed on a reimbursement × application-rate plane and sorted into four quadrants. Inter-specialty reallocation was simulated at 100, 70, and 50% efficiency.

Per-specialist reimbursement was 52.5 million KRW (approximately USD 40,000) in radiology (n = 4,247) and 2,668.6 million KRW (approximately USD 2.04 million) in radiation oncology (n = 330). The resulting ratio was 50.8-fold. Coefficient of variation exceeded 90% in both years. Five specialties combined above-median reimbursement with sub-100% application rates; seven showed the reverse pattern. Utilization-volume triangulation confirmed that per-specialist reimbursement was strongly correlated with claims per specialist (Spearman ρ = 0.74) and patients per specialist (ρ = 0.66), supporting its interpretation as a workload-related indicator. The rank-order association between reimbursement and application rate was not statistically detectable (ρ = 0.180; 95% confidence interval, -0.24 to 0.54; p = 0.400), and the study was underpowered for this secondary test. A counterfactual calculation, presented as an upper-bound illustration rather than a policy projection, indicated that relocating 100 specialists from lower-reimbursement to higher-reimbursement quadrants at 70% efficiency corresponded to 68.8 billion KRW in annual NHI reimbursement.

Across 2 study years, the 50.8-fold gap between these two specialties did not narrow. This dispersion, which reflects NHI-financed resource consumption rather than physician effort alone, is the principal finding. A statistically detectable link between trainee competition and NHI reimbursement was not observed; the secondary correlation test was underpowered, and its null result is not evidence of no association. These findings provide a specialty-level reimbursement baseline for South Korea's workforce allocation debate.