m-Just / OoD-Bench

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Questions about model selection in CelebA_Blond #3

Closed judgingalready closed 2 years ago

judgingalready commented 2 years ago

Excuse me. I have some questions about model selection in CelebA_Blond.

In your paper CelebA uses test-domain validation, that means we choose the model which gets best 'env2_out_acc'. And the distribution of test environment is like this:

                  Male       Female
blond             362         362
not blond         362         362

In the experiment holdout_fraction is set to 0.1. However, the test environment is randomly splited to 9:1. I think it may cause the distribution of two splited dataset to be inconsistent. For example:

env2_in           Male       Female
blond             222         360
not blond         360         362
env2_out          Male       Female
blond             140         2
not blond         2           0

I'm not sure if this will make a difference, or it just doesn't matter.

Looking for you reply, thanks.

m-Just commented 2 years ago

Hi, the example you give can happen but it only happens very rarely. With 20-time different random splits every round of hyperparameter search, even if something like that happens once, I don't think that will make a great difference.

judgingalready commented 2 years ago

Thanks for your quick reply! In my experiments, sometimes 'env2_in_acc' is 4% more(or less) than 'env2_out_acc'. It may be acceptable, and I think It would be better to control the distribution of two splited datasets to be the same.

Thank you again!

m-Just commented 2 years ago

Thank you for letting us know! Please also note that the small sample size is another reason for the variation in the difference between in and out split.