twoway line code

[Martin Imelda Borg]

Hi I am trying to construct a graph with 2 y-axis and trying to label the y axis, with one y-axis being QALY and the second Y axis being Cost

I've tried the below

twoway (line UKrcost age, lpattern(dash) lcolor(red)) ///
       (line ukq age, lpattern(dash) lcolor(dkgreen) yaxis(2)) ytitle("QALY")///
       (line tkrcost age, lcolor(red)) ytitle("Cost"///
       (line tkrq age, lcolor(dkgreen) yaxis(2)), ///
       legend(pos(6) rows(2)) note("Cost and QALY graphs for UKR and TKR in the male cohort")

stata returns an error of 2 invalid name....

can you pls help - still waiting for my chatgpt to refresh to give me some insight!

[Nick Cox]

The punctuation is awry here. You have at least one missing parenthesis and Stata is getting confused.

I can't test any of this as you don't give a data example -- that seems rare in your posts despite your long history on Statalist.


This has a slightly better chance of working. I use the || syntax on the grounds that there are already many parentheses to keep track of.

twoway line UKrcost age, lpattern(dash) lcolor(red) ///
|| line ukq age, lpattern(dash) lcolor(dkgreen) yaxis(2) ytitle("QALY") ///
|| line tkrcost age, lcolor(red) ytitle("Cost") ///
|| line tkrq age, lcolor(dkgreen) yaxis(2) ///
legend(pos(6) rows(2)) note("Cost and QALY graphs for UKR and TKR in the male cohort")

I don't know whether you'd be better off with one graph for Cost and one for QALY.