An NNT of Eight Can Mean a Near-Cure in One Patient and Nothing in Seven

There is a number quietly hiding behind every “this protocol works” claim in medicine — and it explains why the same mold treatment can cure your friend and do nothing for you. It is called the Number Needed to Treat.

What NNT means

NNT is how many people have to receive a treatment for one of them to benefit. An NNT of 1 is a miracle drug — everyone helped. Higher numbers mean fewer helped per person treated. It is the honest scorecard of a therapy.

The secret inside the average

Here is what the number hides: an NNT of eight can describe two completely different realities. It might mean a weak effect spread thinly across everyone — or a near-cure in one person and nothing at all in the other seven. The arithmetic cannot tell them apart.

An NNT of eight can mean a near-cure in one patient and nothing in seven. The arithmetic cannot tell them apart — but the clinic can, because the seven keep coming back. — Andrew Heyman, MD

Why one-size mold protocols run a high NNT

Mold illness is heterogeneous — remember the four phenotypes. Give everyone the same protocol and you are guaranteed to help the subgroup it fits and miss the rest. The relapses are not bad luck or “complex patients”; they are the predictable cost of averaging.

To standardize a heterogeneous disease is to choose a high NNT — and to call the resulting relapses someone else’s complexity. — Andrew Heyman, MD

The fix: find the responder first

The single move that drives NNT toward one is matching the treatment to the patient’s actual biology — identifying which subgroup they are in before treating, rather than after they fail. That is the whole case for precision over average. So if a protocol that “works” did not work for you, the honest reading may not be that you are difficult. It may be that you were treated as an average of people you are not.