Capturing Row and Column Semantics in Transformer Based Question Answering over Tables
This work addresses the challenge of efficient and accurate table-based question answering for applications like online QA systems, though it is incremental as it builds on existing transformer architectures.
The paper tackles the problem of question answering over tables by proposing two transformer-based models that achieve high accuracy without specialized pre-training, with results including up to ~98% Hit@1 accuracy on WikiSQL and outperforming state-of-the-art methods by ~3.4% and ~18.86% in precision.
Transformer based architectures are recently used for the task of answering questions over tables. In order to improve the accuracy on this task, specialized pre-training techniques have been developed and applied on millions of open-domain web tables. In this paper, we propose two novel approaches demonstrating that one can achieve superior performance on table QA task without even using any of these specialized pre-training techniques. The first model, called RCI interaction, leverages a transformer based architecture that independently classifies rows and columns to identify relevant cells. While this model yields extremely high accuracy at finding cell values on recent benchmarks, a second model we propose, called RCI representation, provides a significant efficiency advantage for online QA systems over tables by materializing embeddings for existing tables. Experiments on recent benchmarks prove that the proposed methods can effectively locate cell values on tables (up to ~98% Hit@1 accuracy on WikiSQL lookup questions). Also, the interaction model outperforms the state-of-the-art transformer based approaches, pre-trained on very large table corpora (TAPAS and TaBERT), achieving ~3.4% and ~18.86% additional precision improvement on the standard WikiSQL benchmark.