ENH: Include directionality of feature association in beeswarm plot

[karchern]

Problem Description

First of all, thanks for the idea and implementartion!

We're adopting SHAP values in our model evaluations and find them very useful overall but struggle with the fact that there seems to be no established, programmatic way of determining directionality (think of + vs - coefficients in linear models and how this helps interpretation strongly).

From beeswarm plots, one can read the directionality of the top features by comparing where left/right of x==0 the red/blue dots concentrate. But this visual aid does not allow us to programmatically extract this info.

Alternative Solutions

One solution would be to compute spearman correlations between feature values and shap values. In our hands, this is very reliable and in essence equivalent to what our eye is doing when reading the beeswarm plot.

Do you think this a sensible approach? If approach sounds sensible perhaps one could add the directionality of each feature as a little symbol (perhaps +/- sign somewhere close to the y-axis in the beeswarm plot)?

If this sounds good I'd be happy to issue a PR.

Additional Context

No response

Feature request checklist

• I have checked the issue tracker for duplicate issues.
• I'd be interested in making a PR to implement this feature