TaCube: Pre-computing Data Cubes for Answering Numerical-Reasoning Questions over Tabular Data
Fan Zhou, Mengkang Hu, Haoyu Dong, Zhoujun Cheng, Shi Han, Dongmei Zhang
TL;DR
TaCube addresses numerical reasoning over tabular data by pre-computing a data-cube of aggregations and arithmetic, then feeding these cube items alongside the original table into decoder-based PLMs. It introduces cube_ext operators to broaden reasoning beyond simple aggregations, and offers rule-based generation coupled with neural ranking to produce compact, question-sensitive cubes. Empirically, TaCube achieves state-of-the-art or near-SOTA results on TAT-QA and WikiTQ, with especially large gains on numerical reasoning tasks such as sum, average, subtraction, and division. The approach is presented as a general, portable pre-computation technique that can enhance various NR frameworks for table QA.
Abstract
Existing auto-regressive pre-trained language models (PLMs) like T5 and BART, have been well applied to table question answering by UNIFIEDSKG and TAPEX, respectively, and demonstrated state-of-the-art results on multiple benchmarks. However, auto-regressive PLMs are challenged by recent emerging numerical reasoning datasets, such as TAT-QA, due to the error-prone implicit calculation. In this paper, we present TaCube, to pre-compute aggregation/arithmetic results for the table in advance, so that they are handy and readily available for PLMs to answer numerical reasoning questions. TaCube systematically and comprehensively covers a collection of computational operations over table segments. By simply concatenating TaCube to the input sequence of PLMs, it shows significant experimental effectiveness. TaCube promotes the F1 score from 49.6% to 66.2% on TAT-QA and achieves new state-of-the-art results on WikiTQ (59.6% denotation accuracy). TaCube's improvements on numerical reasoning cases are even more notable: on TAT-QA, TaCube promotes the exact match accuracy of BART-large by 39.6% on sum, 52.5% on average, 36.6% on substraction, and 22.2% on division. We believe that TaCube is a general and portable pre-computation solution that can be potentially integrated to various numerical reasoning frameworks
