Youden Index

Evaluates the performance of a diagnostic test to be used in conjunction with receiver operating characteristic (ROC) analysis.

Refer to the text below the calculator for more information about the parameters and formulas used.


The Youden Index represents a summary measurement of the receiver operating characteristic (ROC) curve for the accuracy of a diagnostic test with ordinal or continuous endpoints.

It originates from the work of Youden WJ. back in 1950 and gives equal weight to false positive and false negative values, so it can be concluded that when two tests have the same index, it means they have the same proportion of total misclassified results.


J Statistic Youden Index = SNS + SPC – 1

OR

J Statistic Youden Index = [TP / (TP + FN)] + [TN / (FP + TN)] - 1

Youden Index ranges between 0 and 1, with 0 values indicating that a diagnostic test gives the same proportion of positive results for groups with and without the disease. 1 values indicate that there are no false positives or false negatives.


Note: If sensitivity & specificity are unknown please go to Method 2 tab.

Sensitivity (SNS)
Specificity (SPC)
  Embed  Print  Share 
True Positives (TP)
True Negatives (TN)
False Positives (FP)
False Negatives (FN)
Print 

Send Us Your Feedback

Steps on how to print your input & results:

1. Fill in the calculator/tool with your values and/or your answer choices and press Calculate.

2. Then you can click on the Print button to open a PDF in a separate window with the inputs and results. You can further save the PDF or print it.

Please note that once you have closed the PDF you need to click on the Calculate button before you try opening it again, otherwise the input and/or results may not appear in the pdf.


 

J Statistic (Youden Index) Explained

The Youden Index represents a summary measurement of the receiver operating characteristic (ROC) curve for the accuracy of a diagnostic test with ordinal or continuous endpoints.

It originates from the work of Youden WJ. back in 1950 and gives equal weight to false positive and false negative values, so it can be concluded that when two tests have the same index, it means they have the same proportion of total misclassified results.

  • J Statistic Youden Index = Sensitivity + Specificity – 1

OR

  • J Statistic Youden Index = [TP / (TP + FN)] + [TN / (FP + TN)] - 1

Where:

TP = True Positives

TN = True Negatives

FP = False Positives

FN = False Negatives

Youden Index ranges between 0 and 1, with 0 values indicating that a diagnostic test gives the same proportion of positive results for groups with and without the disease. A value of 1 indicates that there are no false positives or false negatives.

The J Statistic can be used in conjunction with receiver operating characteristic (ROC) analysis, where the index is defined for all points of the ROC curve. The maxim value of the index can then be used as a cut-off for numerical diagnostic tests.

 

References

Original reference

Youden WJ. Index for rating diagnostic tests. Cancer. 1950; 3(1):32-35.

Other references

Ruopp MD, Perkins NJ, Whitcomb BW, Schisterman EF. Youden Index and optimal cut-point estimated from observations affected by a lower limit of detection. Biom J. 2008; 50(3):419-30.

Shan G. Improved Confidence Intervals for the Youden Index. PLoS One. 2015; 10(7):e0127272.

Nakas CT, Alonzo TA, Yiannoutsos CT. Accuracy and cut-off point selection in three-class classification problems using a generalization of the Youden index. Stat Med. 2010; 29(28):2946-55.


Specialty: Research

Year Of Study: 1950

Article By: Denise Nedea

Published On: June 29, 2020 · 12:00 AM

Last Checked: June 29, 2020

Next Review: June 29, 2025