[Covid-19: Twin Method for Verifying Real-World Effectiveness Under Everyday Conditions].

The positive side of the Covid-19 pandemic is that it has provided a stimulation for innovations. As an example, we discuss the Pragmatic Controlled Trial (PCT), a twin study that can be used to confirm the real-world effectiveness (RWE) of health services under the non-standardized conditions of everyday care. Proof of the RWE could generally be important for health services with conditional approval. The PCT uses the Bayesian principle instead of randomization. It enables care under non-standardized everyday conditions and, by describing the endpoint-specific risks of each individual patient and by classifying the interventions, creates an unbiased evaluation in a non-experimental, but risk-stratified and controlled study. Patients expect a timely solution to their health problems. Until now, science has required sufficiently well-founded results before approving an innovation. The Covid-19 pandemic has shown that the demand for immediate and best possible care can be met through the conditional approval of a new care principle. With the PCT, we describe a procedure with which, after conditional approval, the missing data can be collected in order to successfully complete the approval process.