Multiple Networks are More Efficient than One: Fast and Accurate Models via Ensembles and Cascades

Recent work on efficient neural network architectures focuses on discovering a solitary network that can achieve superior computational efficiency and accuracy. While this paradigm has yielded impressive results, the search for novel architectures usually requires significant computational resources. In this work, we demonstrate a simple complementary paradigm to obtain efficient and accurate models that requires no architectural tuning. We show that committee-based models, i.e., ensembles or cascades of models, can easily obtain higher accuracy with less computation when compared to a single model. We extensively investigate the benefits of committee-based models on various vision tasks and architecture families. Our results suggest that in the large computation regime, model ensembles are a more cost-effective way to improve accuracy than using a large solitary model. We also find that the computational cost of an ensemble can be significantly reduced by converting them to cascades, while often retaining the original accuracy of the full ensemble.