Enter the true negative rate and the false-negative rate into the calculator to determine the negative predicted value.

## Negative Predictive Value Formula

The following formula is used to calculate a negative predictive value.

NPV = TNR / (TNR + FNR)
• Where NPV is the negative predictive value
• TNR is the true negative rate
• FNR is the false negative rate

The true negative rate refers to the proportion of actual negative cases that are correctly identified as negative by a diagnostic test or model.

The false negative rate refers to the proportion of negative results that are incorrectly identified as positive in a diagnostic test or classification model.

## Negative Predictive Value Definition

Negative Predictive Value (NPV) is a statistical measure that assesses the probability of a negative test result accurately indicating the absence of a particular condition or disease in an individual. It is calculated by dividing the number of true negative results by the sum of true negative and false positive results and is expressed as a percentage.

NPV is crucial because it helps determine the reliability of a diagnostic test in ruling out a condition. A high NPV indicates that a negative test result is highly likely accurate, meaning that the individual is unlikely to have the condition. This is particularly important when the condition being tested for is severe or potentially life-threatening.

For example, in medical screening, a high NPV is desirable as it assures that a negative test result can reassure patients, allowing them to avoid unnecessary further testing or treatment. Similarly, in population-based screening programs, a high NPV is important to minimize the chances of false-negative results, ensuring that individuals without the condition are not mistakenly identified as being disease-free.

## Negative Predictive Value Example

How to calculate negative predictive value?

1. First determine the true negative rate.

Calculate the rate at which a true negative test result is found.

2. Next, determine the false negative rate.

Calculate the rate at which a negative test results in a false negative.

3. Finally, calculate the negative predictive value.

Using the formula, calculate the NPV.

## FAQ

What is a negative predictive value?

A negative predictive value is a probability or chance that people who get a negative test result, actually do not have whatever was being tested for. In other words, it’s a measure of how accurate a given test is.

What is a positive predictive value?

A positive predictive value is a probability that you actually have a disease given positive test results.