Enter the control group % and the experiment group % into the NNT calculator. The calculator will display the total number of patients that need to be treated to achieve an endpoint.

## Number Needed to Treat Formula

The following formula is used to calculate the total number of patients that need to be treated in order to achieve a result.

NNT=1/ARR
• Where NNT is the number of patients that need to be treated
• ARR is the absolute risk reduction

Furthermore, ARR can be calculated through the following equation.

ARR=CER - EER
• Where CER is the control event rate
• EER is the experiment event rate

## Number Needed to Treat Definition

Number Needed to Treat (NNT) is a statistical measure used in clinical research to quantify the effectiveness of a medical intervention or treatment. It represents the number of patients who need to be treated to prevent one additional outcome of interest, such as an adverse event or a specific health outcome.

NNT is calculated by comparing the outcome rates in two groups: the treatment group and the control group. The difference in the outcome rates between the two groups is then used to determine the NNT.

A lower NNT indicates a more effective treatment, as fewer patients need to be treated to achieve the desired outcome.

NNT helps clinicians and researchers assess the potential benefits and risks associated with a particular intervention. By quantifying the number of patients needed to be treated to observe a positive outcome, NNT helps inform medical decisions, resource allocation, and patient care.

## How to calculate number needed to treat?

How to calculate a number needed to treat?

1. First, measure the control event rate

This will be the percent treated in the control event.

2. Next, measure the experiment event rate

This will be the percent treated in the experiment.

3. Lastly, calculate the NNT

Using the formula above and the information from steps 1-2 to calculate the NNT

## FAQ

What is NNT?

NNT stands for the number needed to treat. It’s a term used in medicine to describe the total number of patients needed to be treated in order to achieve a given result.