Review for NeurIPS paper: Balanced Meta-Softmax for Long-Tailed Visual Recognition

The paper first shows that the softmax gives a biased gradient estimation under the long-tailed setup, and proposes a balanced softmax to accommodate the label distribution shift between training and testing. Theoretically, the authors derive the generalization bound for multiclass softmax regression. They then introduce a balanced meta-softmax procedure, using a complementary meta sampler to estimate the optimal class sample rate and further improve long-tailed learning.Experiments demonstrate that this outperforms SOTA long-tailed classification solutions on both visual recognition and instance segmentation tasks. The paper was reviewed by the four reviewers that found strengths and weaknesses. The strengths were the fact that the idea is intuitive and simple to implement, the theoretical derivations in support of the method, and the good results.