Why is fbeta default threshold 0.2?

I’m working on multilabel text classification and noticed that the default value for the fbeta metric (https://docs.fast.ai/metrics.html#fbeta) is 0.2.
Shouldn’t the default value be 0.5 like in accuracy_thresh? My reasoning is that since sigmoid=True the scores should be interpreted as probabilities and thus the 0.2 threshold is too low.

I have the same question as Martin, and I feel a default value of 0.5 may be better. I think it may have been set to 0.2 because it gave the best results with lesson 3’s planet dataset where the concept was explained.

Fell free to use any value you want. We defaulted it to one we thought was good but it’s of course dependent of the task you have :wink:

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Thanks, Sylvain!