# Cstat

##### C Statistic (Area Under the ROC Curve)

Calculate the C statistic (equivalent to the area under the Receiver Operating Characteristic Curver ROC) for a logistic regression model, a measure of goodness of fit for binary outcomes in a logistic regression model.

- Keywords
- mod

##### Usage

```
Cstat(x, ...)
"Cstat"(x, ...)
"Cstat"(x, resp, ...)
```

##### Arguments

- x
- the linear model
- resp
- the response variable
- ...
- further arguments to be passed to other functions.

##### Details

Values for this measure range from 0.5 to 1.0. A value of 0.5 indicates that the model is no better than chance at making a prediction of membership in a group and a value of 1.0 indicates that the model perfectly identifies those within a group and those not. Models are typically considered reasonable when the C-statistic is higher than 0.7 and strong when C exceeds 0.8.

Confidence intervals for this measure can be calculated by bootstrap.

##### Value

##### References

Hosmer D.W., Lemeshow S. (2000) Applied Logistic Regression (2nd Edition). New York, NY: *John Wiley & Sons*

##### See Also

##### Examples

```
r.glm <- glm(Survived ~ ., data=Untable(Titanic), family=binomial)
Cstat(r.glm)
```

*Documentation reproduced from package DescTools, version 0.99.19, License: GPL (>= 2)*