7.4 Ethics and scientific research. The authors of a paper on clinical research and ethics stated the following.

For a clinical research protocol to be ethical, the methods must be valid and practically feasible: the research must have a clear scientific objective; be designed using accepted principles, methods, and reliable practices; have sufficient power to definitively test the objective; and offer a plausible data analysis plan. In addition, it must be possible to execute the proposed study.

Do you think this rules out observational studies as “ethical”?