Greetings - my first post, so apologies for being ignorant of conventions, any directions/instructions gratefully received...

Using Ellip I noticed that changing the 'level' option to 80, 90, 95 doesn't change the size of the ellipse., while using the constant option (set to 3.2, 4.6, 6) works

So...
ellip yvar xvar , level(95) plot(scatter yvar xvar)
and
ellip yvar xvar , level(80) plot(scatter yvar xvar)
are identical (and r(c) doesn't change - returned boundary constant)

ellip yvar xvar , constant(3.2) plot(scatter yvar xvar)
and
ellip yvar xvar , constant(6) plot(scatter yvar xvar)
look correct (and r(c) confirms)

Apologies if this is just some basic misunderstanding on my part, or previously reported

The manual* says that further eclipses can be overlaid using the plot option - I can't get this to work (...not a plot type)
The only way to overlay ellipses seems to be to reshape data long and 'overlay by...'

* Graphing confidence ellipses: An update of ellip for Stata 8. The Stata Journal (2004) 4, Number 3, pp. 242–256
p248: 'plot(#) adds other plots to the generated graph... Examples of such plots are another confidence ellipse...