Such systems allow users to formulate questions with greater flexibility.
although state-of-the-art systems have achieved a high accuracy of 80% to 90% (Dong and Lapata, 2016) on well-curated datasets like GEO (Zelle and Ray, 1996) and ATIS (Zettlemoyer and Collins, 2007), the best accuracies on datasets with questions formulated by real human users, e.g., WebQuestions (Berant et al., 2013), GraphQuestions , and WikiSQL (Zhong et al., 2017), are still far from enough for real use, typically in the range of 20% to 60%.