On 2017 Sep 09, Michael Allen commented:

The equations for disease impact number (DIN) and population impact number (PIN) are confusing according to the following examples in which the proportion with the diseased exposed to the treatment and the proportion of the population with the disease are both 0.1

In example 1 NNT=100; DIN=1000; PIN=10000 In example 2 NNT=10; DIN=100; PIN=1000

In these examples the only difference is the NNT (100 in example 1; 10 in example 2). A smaller NNT indicates a larger effect.

However changing the NNT from 100 to 10 leads to a smaller DIN and PIN indicating a smaller effect.

I have checked the way I calculated DIN and PIN against the authors' examples and they are correct.

It seems the authors' equations for the DIN and PIN may be incorrect. Or am I missing something?

On 2017 Sep 09, Michael Allen commented:

The equations for disease impact number (DIN) and population impact number (PIN) are confusing according to the following examples in which the proportion with the diseased exposed to the treatment and the proportion of the population with the disease are both 0.1

In example 1 NNT=100; DIN=1000; PIN=10000 In example 2 NNT=10; DIN=100; PIN=1000

In these examples the only difference is the NNT (100 in example 1; 10 in example 2). A smaller NNT indicates a larger effect.

However changing the NNT from 100 to 10 leads to a smaller DIN and PIN indicating a smaller effect.

I have checked the way I calculated DIN and PIN against the authors' examples and they are correct.

It seems the authors' equations for the DIN and PIN may be incorrect. Or am I missing something?