[ENH] merge metric files into _base_metrics.py, rename _disparities.py to fairness_metrics.py, and move _input_manipulations.py to the utils module

[romanlutz]

Description

closes #455

This PR merges metric files into _base_metrics.py, renames _disparities.py to _fairness.py, and moves _input_manipulations.py to the utils module. None of the contents of the migrated functions was changed.

Tests

• no new tests required
• new tests added
• existing tests adjusted

Documentation

• no documentation changes needed
• user guide added or updated
• API docs added or updated
• example notebook added or updated

Screenshots

[hildeweerts]

Other-ml tests seem to have failed due to a deprecation error in xgboost: "UserWarning: use_label_encoder is deprecated in 1.7.0." According to the deprecation tracker users need to do label encoding manually. We set it to False so we just need to remove use_label_encoder=False from our code.

EDIT: nvm I see you've already opened #1204 to fix this

[hildeweerts]

Thanks, @romanlutz! The renaming makes things so much clearer., IMO. There are a few codecov warnings we should look into, other than that this looks good to me!

[riedgar-ms]

When it comes to naming, I thought we preferred disparity to fairness on the grounds that the former was definitely measurable, whereas the latter was not?

[romanlutz]

When it comes to naming, I thought we preferred disparity to fairness on the grounds that the former was definitely measurable, whereas the latter was not?

I'm following the instructions from the issue #455 🙂 I don't care either way tbh. It's just a file name 🙂 @hildeweerts do you have thoughts?

[hildeweerts]

Given that we refer to this type of metric as fairness metric a lot throughout the user guide I think using "fairness metric" is perfectly sensible :)

[romanlutz]

There are a few codecov warnings we should look into, other than that this looks good to me!

I didn't change any code, so codecov is probably angry that file coverage went down or something like that.

Actually, looking at the specific files it points out... I didn't touch those or anything related at all. Must be a codecov bug?

[hildeweerts]

Actually, looking at the specific files it points out... I didn't touch those or anything related at all. Must be a codecov bug?

I think these files probably predate our installment of codecov, so maybe it's not a bug but an actual lack of coverage? In any case I don't think it is something that needs to be fixed in this PR.

[riedgar-ms]

I've no objection to the consolidation and reorganisation of files, but as I recall, calling them 'disparity metrics' was a pretty deliberate choice. That said, it's not user facing either.

[MiroDudik]

My sense is that we have since departed from calling them "disparity metrics". I'm more comfortable calling them "fairness metrics"... To be parallel with _base_metrics.py, maybe we should call the old _disparities.py something like _fairness_metrics.py?

[riedgar-ms]

OK, I'm fine with the renaming then.