# Drawing an ROC curve

#### Abder-Rahman Ali

##### New Member
If I have values for sensitivity and specificity fora group of studies for example like this:

sensitivity specificity
----------- -----------
66.3% 74.7%
87.2% 65.9%
56.4% 76.4%
79.5% 94.3%

How can I make an ROC curve for such values? Do I divide them by 100 for example and just put the values in the curve straightforward? Or, how exactly does the process work out?

Thanks.

#### Masteras

##### TS Contributor
the roc curves are y-axis sensitivity and x-axis 1-specificity or 100-specificity. Then you just plot the numbers and connect them with a line to see how it goes.

#### Abder-Rahman Ali

##### New Member
the roc curves are y-axis sensitivity and x-axis 1-specificity or 100-specificity. Then you just plot the numbers and connect them with a line to see how it goes.
Thanks a lot for your clarification. But, shouldn't I divide the values I have by 100? As I saw some curves and the range for sensitivity and specificity was 0-1.

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#### Masteras

##### TS Contributor
Yes you have to divide it. Very good.