Graph with two y axes, one linear and one inverse

[Markos Valsamis]

Hello,

I would like to generate a graph where one y-axis scale is linear (0 to x), and the opposite (yaxis(2)) scale is the inverse of this (1/x), and hence in reverse. An example of what I want to achieve is below. Lets take the variables being NNT (left y axis), ARR (right y axis) and _t (x axis) for the example below. Many thanks in advance.

[Nick Cox]

The trick is to plot in terms of the reciprocal but to arrange for axis labels to show values on the original scale. See

https://journals.sagepub.com/doi/pdf...867X0800800113

https://journals.sagepub.com/doi/pdf...6867X221141058 -- write-up of mylabels (used below)

You need a two step given NNT and its bad sibling.

This isn't the graph you want, but it has the desired labels on the left.

clear 
set obs 7
gen x = _n 
range whatever -0.1 0.5 

gen NNT = 1/whatever 

mylabels 2 5 10 20, myscale(1/@) local(yla1)

mylabels 20 10, myscale(-1/@) local(yla2)

scatter whatever x, yla(`yla1' `yla2')

[Markos Valsamis]

Thanks very much Nick Cox , that worked great!