# Interactive dot diagram

Command: | Statistics ROC curves Interactive dot diagram |

## Description

In addition to the ROC curve, MedCalc offers a second graphical display to study the accuracy of a diagnostic test, namely an *Interactive dot diagram*.

## Required input

**Variable**: select the variable of interest.**Classification variable**: select a dichotomous variable indicating diagnosis (0=negative, 1=positive).If your data are coded differently, you can use the Define status tool to recode your data.**Filter**: (optionally) a filter in order to include only a selected subgroup of cases (e.g. AGE>21, SEX="Male").**Options:**Logarithmic transformation of data.

## Graph

In the graph the data of the negative and positive groups are displayed as dots on two vertical axes. Initially, a horizontal line indicates the cut-off point with the best separation (minimal false negative and false positive results) between the two groups. The corresponding test characteristics *sensitivity* and *specificity* are shown at the right side of the display.

By clicking in the display, you can move the horizontal line to other values or cut-off points.