We spend many billions of dollars each year on the discovery and development of new drugs, but almost none of it addresses two crucial questions: How do these new therapies compare with already known ones? What are the relative benefits and harms in a particular situation, for a person like you?

Such questions can best be answered by comparative effectiveness research.

To get approval from the Food and Drug Administration, drugs must be proved both effective and safe. The costs of doing this are significant, and they are most often borne by the pharmaceutical industry.

But the F.D.A.’s bar, while meaningful, often isn’t very useful for what physicians and patients really care about every day: how effective and safe drugs are compared with one another.

Real-World Questions

Consider antibiotics. In my work as a pediatrician, questions about their use come up a lot. Which drug is the best first-line therapy for which common illnesses? We don’t know. How long should we treat for different infections? We don’t know. What are the relative trade-offs between benefits and side effects in different patients in different circumstances? We don’t know.