Many countries face challenges like impending retirement waves, negative
population growth, or a suboptimal distribution of resources across medical
sectors and fields in supplying their healthcare systems with adequate
staffing. An increasing number of countries therefore employs quantitative
approaches in health workforce supply forecasting. However, these models are
often of limited usability as they either require extensive individual-level
data or become too simplistic to capture key demographic or epidemiological
factors. We propose a novel population-dynamical and stock-flow-consistent
approach to health workforce supply forecasting complex enough to address
dynamically changing behaviors while requiring only publicly available
timeseries data for complete calibration. We apply the model to 21 European
countries to forecast the supply of generalist and specialist physicians until
2040. Compared to staffing levels required to keep the physician density
constant at 2016 levels, in many countries we find a significant trend toward
decreasing density for generalist physicians at the expense of increasing
densities for specialists. These trends are exacerbated in many Southern and
Eastern European countries by expectations of negative population growth. For
the example of Austria we generalize our approach to a multi-professional,
multi-regional and multi-sectoral model and find a suboptimal distribution in
the supply of contracted versus non-contracted physicians. It is of the utmost
importance to devise tools for decision makers to influence the allocation and
supply of physicians across fields and sectors to combat imbalances