[Care supply projections as a building block of evidence-based health services planning].

INTRODUCTION: As part of the measures to combat the shortage of general practitioners (GPs) particularly in rural areas, health services planning is becoming increasingly important. METHODS: This paper shows how the quality of health services planning can be improved by combining population forecasts and physician number forecasts based on the cohort component method. On the basis of already available data (population data and doctors' registers), developments in the levels of care supply can be predicted on a small regional scale. The regional and temporal differentiation allows for early identification of specific needs for action. However, it is important to consider limitations in the interpretation of results. RESULTS: The example of Lower Saxony shows that by 2035 a decline of more than 20% in the number of GPs is expected. At the same time, regions are affected to varying degrees, and even within the more vulnerable rural areas there are heterogeneous developments which require regionally adapted responses. CONCLUSION: The greater the gap between supply and demand, the more important high-quality planning for efficient allocation of health services becomes. Against this background, care supply projections can serve as a useful building block of evidence-based care planning.