Deliberate experiments designed to assess the value and merits of therapeutic processes in patients are a critical part of modern medicine. These experiments are rarely easy, and they can be costly and time-consuming. If badly designed, they can even be a threat to patients. The efficiency of such experiments is very important. Over time, randomized controlled trials (RCTs) have been developed and have evolved to ensure clinical relevance, but it is impossible to ensure that everyone who has a disease is included in a study for reasons of scientific interpretation. I will use historical context and how research has evolved to explore this topic.