Hospital Bias

Asking people about differences between private and public hospitals, you are most likely getting answers that the private hospitals deliver superior patient outcomes. Whereas private hospitals seem to have a positive stigma attached to them, public hospitals commonly have a negative stigma. Scientific evaluations are helpful to set the record straight again. The study published in “The Lancet Regional Health” in 2024 shows that in the simple descriptive statistics on several patient outcome indicators, this is what the data showed between 2026 and 2019. However, a more precise statistical analysis reveals that there is also a selective admission to the private and public hospitals in England. Using so-called instrumental variables approaches that account for the selection process between admission to the 2 types of hospitals (private versus public) most of the differences between the hospital types disappear. The underlying mechanism is a sorting of different patients into the private or public hospitals. Put in easy words, for a routine intervention people tend to chose the private hospital, but the more rare and difficult operations were more likely admitted to public hospitals. The number of co-morbidities (heart disease) is also of importance as they might negatively affect patient outcomes. Jumping to conclusions and reinforcing stigma about public or private provision of services hinders progress and an equitable provision of services.
The analysis of a potential selection bias can reveal the “creaming” effect of private provision of (health) services. Just caring for the “easy” or routine cases and avoiding the more difficult and costly cases has economic advantages, but for society as a whole the costs overall remain the same. A good public service in health is a definite asset.

(Image: Exposition Isa Genzken 2023 in Neue Nationalgalerie Berlin)