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When I was looking at AL query strategies (including random sampling, which I agree should always be included as a baseline), hyperparameter tuning (and model s
by whakim 3y ago
When I was looking at AL query strategies (including random sampling, which I agree should always be included as a baseline), hyperparameter tuning (and model selection more generally) was definitely performed and optimized on a per-strategy basis. (This is a lot of combinations but it's reasonable to prune things that are clearly dead-ends, and that's how we ended up with a non-linear SVC.) We just didn't do it between iterations due to the practical concerns.
I understand the view that from a scientific perspective it is difficult to quantify the utility of a technique if it is providing multiple benefits at the same time. Not necessarily saying that's what's happening here, but it's worth pointing out that you can also look at this from a practical angle.For any given dataset your chosen model and set of hyperparameters probably isn't optimal, so if indeed AL is compensating for suboptimal choices in model selection, that may still be valuable.
Another potentially interesting angle to consider is label imbalance; because we were constructing binary classification problems out of multiclass problems (as discussed earlier), some evidence shows AL strategies outperform random sampling to a significantly greater degree in imbalanced scenarios [1].
I agree with you that we're moving towards a world in which transformer models are so good that zero-shot or few-shot approaches to classification are going to be the way to go. Stuff I did 3 years ago I probably would not do today.
[1] https://aclanthology.org/2020.emnlp-main.638.pdf https://aclanthology.org/2020.emnlp-main.638.pdf
- abhgh 3y agoIt becomes valuable if it either compensates for the lack of hyperparam tuning in all or a broad class of models, or the result is precisely presented to say something like "better than random if the model is a linear svm with C=1". Right now we are somewhere in between where the results are presented to seem somewhat generally useful, but when you tweak the hyperparams you realize that the utility is potentially quite narrow. We either need broad utility or increased rigor in reporting - we cannot abandon both. Yeah that's an interesting paper [1], and label imbalance is a case we have not investigated (we were able to reproduce some results from it - the DAL experiments in Section A.3 "Reproducibility Experiments" in [2] come from there). [1] Active Learning for BERT: An Empirical Study, https://aclanthology.org/2020.emnlp-main.638.pdf https://aclanthology.org/2020.emnlp-main.638.pdf [2] One the Fragility of Active Learners, https://arxiv.org/abs/2403.15744 https://arxiv.org/abs/2403.15744