Without evidence of benefit, an intervention should not be presumed to be beneficial or safe.

- Rogue Medic

The NNT and Merit Badge Meds

Perhaps I am too negative in my interpretation of the research on ACLS medications. What about a more objective assessment – one with a more statistical view of the harms and benefits?

How many patients have to be treated with ACLS (Advanced Cardiac Life Support) drugs in order for one patient to benefit (be resuscitated) from the treatment?

The NNT is a very interesting site. The information is prevented much more succinctly than I usually describe things.

Why NNT?

NNT is a common medical term.

NNT is the Number Needed to Treat – the average number of patients we would need to treat with something in order for one patient to benefit. The flip side is NNH.

NNH is the Number Needed to Harm – the average number of patients we would need to treat with something in order to harm one patient.

This is explained in more detail (including a less than 4 minute YouTube video for those who don’t want to read a lot) at the NNT Explained page. Understanding the material presented in the video is very important for understanding the actual benefit of a treatment, rather than the potential benefit that is given by those promoting any treatment.

Once you understand this, you will be able to see that many treatments require huge numbers of participants because the NNT is so large. A large NNT means a small benefit (in numbers). Just because only a small number of patients benefit, does not mean that the benefit is small. The amount of benefit for those who do benefit is also important. This is one of the reasons we spend so much time treating cardiac arrest.

While the NNT for cardiac arrest is large, the benefit is lives saved. There are few benefits as important as that. As the method of CPR improves, the NNT drops because the treatment helps more patients. The NNT is a great site to look around and get a quick idea of the relative benefits of many different treatments. Go browse the NNT.



  1. Valuable info. Lucky me I found your site by accident, I bookmarked it.


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