Weighted Youden index

[astamm]

Youden index is often used in classification problems when one wants to jointly maximize sensitivity and specificity. By definition, it gives equal weight to both but, in some contexts, it might be relevant to give more weight to one or the other.

We created a package called {mupet} that implements weighted Youden index.

But I think it could be nice to have an option in yardstick::j_index() to let the user choose the weights, with a default that makes it the usual balanced formula to keep existing code unbroken. Would you consider this feature request? If so, would you like to receive a corresponding PR?

Thanks.