# What is a good Youden index?

## What is a good Youden index?

The cut-off point for having an acceptable Youden index is 50%. Any value below 50% denote an overall lack of the diagnostic test to detect either disease or health.

## What does Youden index measure?

The Youden Index is a frequently used summary measure of the ROC (Receiver Operating Characteristic) curve. It both, measures the effectiveness of a diagnostic marker and enables the selection of an optimal threshold value (cutoff point) for the marker.

**Is ROC Index same as AUC?**

ROC is a probability curve and AUC represents the degree or measure of separability. It tells how much the model is capable of distinguishing between classes.

### What is an acceptable AUC ROC?

AREA UNDER THE ROC CURVE In general, an AUC of 0.5 suggests no discrimination (i.e., ability to diagnose patients with and without the disease or condition based on the test), 0.7 to 0.8 is considered acceptable, 0.8 to 0.9 is considered excellent, and more than 0.9 is considered outstanding.

### How does SPSS calculate Youden index?

COMPUTE Specificity = 1 – @1Specificity. COMPUTE Youden = Sensitivity – @1Specificity.

**How do we interpret ROC curve?**

Classifiers that give curves closer to the top-left corner indicate a better performance. As a baseline, a random classifier is expected to give points lying along the diagonal (FPR = TPR). The closer the curve comes to the 45-degree diagonal of the ROC space, the less accurate the test.

#### What is a Youden plot?

Youden plots are a graphical technique for analyzing interlab data when each lab has made two runs on the same product or one run on two different products. The Youden plot is a simple but effective method for comparing both the within-laboratory variability and the between-laboratory variability.

#### What is KS Youden?

KS (Youden) The maximum distance between the ROC curve and the baseline model. Misclassification Rate (Event) The misclassification rate of the target event level.

**Is AUC the same as accuracy?**

Accuracy is a very commonly used metric, even in the everyday life. In opposite to that, the AUC is used only when it’s about classification problems with probabilities in order to analyze the prediction more deeply. Because of that, accuracy is understandable and intuitive even to a non-technical person.

## What is the C index?

The concordance index or c-index is a metric to evaluate the predictions made by an algorithm. It is defined as the proportion of concordant pairs divided by the total number of possible evaluation pairs.

## What does AUC less than 0.5 mean?

Usually, the AUC is in the range [0.5,1] because useful classifiers should perform better than random. In principle, however, the AUC can also be smaller than 0.5, which indicates that a classifier performs worse than a random classifier.

**What is an ROC index?**

An ROC curve (receiver operating characteristic curve) is a graph showing the performance of a classification model at all classification thresholds. This curve plots two parameters: True Positive Rate.