Can financial retention incentives slow migration? PPP-adjusted salary differentials in Zimbabwe’s donor-dependent health system

Background Large-scale migration of health workers from low-income countries continues to undermine health system capacity, particularly in contexts characterised by fiscal constraint and donor dependence. While retention incentives are widely used to mitigate attrition, their ability to offset international wage differentials remains contested. Zimbabwe provides a salient case, having implemented a long-standing Health Worker Retention Scheme (HWRS), largely financed by external partners, to stabilise critical cadres within the public health sector. Methods We conducted a cross-country comparison of annual remuneration for three cadres; professional nurses, medical officers, and medical specialists, using a purchasing power parity (PPP) framework. Salaries in Zimbabwe, South Africa, the United Kingdom, and the United States were compiled from official public-sector pay schedules and adjusted using International Comparison Program (ICP) 2021 PPP conversion factors. Zimbabwean salaries were analysed under three scenarios: government salary only; government salary plus domestic allowances; and government salary plus domestic and Global Fund-financed HWRS allowances. PPP-adjusted salary gaps were calculated relative to Zimbabwe’s government-only baseline. Results Across all cadres, PPP-adjusted salaries in destination countries substantially exceeded Zimbabwean public-sector earnings. HWRS allowances increased Zimbabwe’s PPP-adjusted salaries by approximately 30% for specialists, 20% for medical officers, and less than 10% for nurses, narrowing, however, not eliminating international differentials. Even under the HWRS scenario, PPP-adjusted salaries in South Africa, the United Kingdom, and the United States remained several multiples higher than those in Zimbabwe. Conclusion Donor-financed retention incentives meaningfully improve Zimbabwe’s relative salary position but do not fundamentally alter the international remuneration gradient that underpins health worker migration. In donor-dependent health systems, such schemes function as stabilising mechanisms rather than long-term solutions. Sustainable retention will require complementary strategies addressing career progression, working conditions, and global governance of health worker mobility.