Quick Question-

[Mah]

and its kinda stupid too, but I just wanna make sure-

NNT is the same thing as NNH, yes? with treatment being the focus in NNT and harmful effect being the focus in NNH?

They're both calculated as the inverse of Attributable risk?
Is there a difference between attributable risk and attributable risk reduction?

Sorry if it seems really dumb to you, but please do tell me ASAP!

---

Members don't see this ad.

 

[Mah]

nevermind..

 

[DrTacoElf]

A negative number would not be presented as a NNT, rather, as the intervention is harmful, it is expressed as a number needed to harm (NNH). The units of the aforementioned probabilities are expressed as number of events per subject (see worked out example below); therefore, the inverse NNH will be number of subjects (required) per event.