Shading AUC on ROC curve?

[Sarah Romano]

Is it possible to shade with color the area under the curve on an ROC curve in stata? I can't find any resources documenting this. If it is possible, could you please help me out with some code? I'm currently just running a basic roctab.

Much appreciated!

[Justin Niakamal]

There might be an easier way, but you could modify the source code for roctab to accomplish what you want (just save it under a different name of course). For example, changing

connected `sens' `spec'

to

rarea `sens' `spec' `spec'

Example

webuse hanley, clear
my_roctab disease rating, graph

[Sarah Romano]

Thank you!

[Senema John]

Hey Justin, I am little bit confused. Can you explain further how to change the codes and generate my_roctab. Thanks

[Andrew Musau]

findfile roctab.ado
doedit "`r(fn)'"

edit and save as "my_roctab.ado".

[Senema John]

@ Andrew : Is there a simple code I can just run

[Andrew Musau]

As it is an official command, it accepts twoway options:

webuse hanley, clear
roctab disease rating, graph plotopts(recast(area))

[Senema John]

Thank you Andrew. This is really helpful. Do you know how I can remove the shade underneath the reference line that runs through the middle? Thanks again.

[Andrew Musau]

You can try specifying options for the reference line. But that will require that you turn off the grid lines.

webuse hanley, clear
roctab disease rating, graph plotopts(recast(area) ///
xlab(,nogrid) ylab(,nogrid) lc(white))  ///
rlopts(recast(area) color(white) lc(white))

[Senema John]

Thank you so so much Andrew. One more last time. What if I want to plot more than on graph on the curve using the above information. I tried it but it was saying the plot option not allowed.
Thanks again Andrew.

[Senema John]

I mean comparing several AUC

[Bruce Weaver]

Nice example in #9, Andrew Musau. It took me a while to find how to do it, but I would add fintens(inten30) to lighten up that shaded area a bit. ;-)

roctab disease rating, graph plotopts(recast(area) fintens(inten30) ///
xlab(,nogrid) ylab(,nogrid) lc(white))  ///
rlopts(recast(area) color(white) lc(white))

[Senema John]

Hey Bruce. Do you know how I can add more variables to compare more than one AUC on the same graph with different shades of color? Thanks

[Bruce Weaver]

Hi Senema. No, I don't know how to do that off the top of my head.

[Andrew Musau]

Nice example in #9, Andrew Musau. It took me a while to find how to do it, but I would add fintens(inten30) to lighten up that shaded area a bit. ;-)

Thanks Bruce, it looks much nicer that way.

Thank you so so much Andrew. One more last time. What if I want to plot more than one graph on the curve using the above information. I tried it but it was saying the plot option not allowed.
Thanks again Andrew.

You can include an additional twoway graph using -addplot()-, but roctab does not allow you to plot multiple overlaid ROC curves. If you need to do that, you are probably better off extracting the data and switching to twoway. Instead of asking one thing after another, I would suggest that you start a new thread and ask a question relating to your exact problem.