Assessing the quality of answers autonomously in community question-answering

摘要

Community question-answering (CQA) has become a popular method of online information seeking. Within these services, peers ask questions and create answers to those questions. For some time, content repositories created through CQA sites have widely supported general-purpose tasks; however, they can also be used as online digital libraries that satisfy specific needs related to education. Horizontal CQA services, such as Yahoo! Answers, and vertical CQA services, such as Brainly, aim to help students improve their learning process via Q&A exchanges. In addition, Stack Overflow—another vertical CQA—serves a similar purpose but specifically focuses on topics relevant to programmers. Receiving high-quality answer(s) to a posed CQA query is a critical factor to both user satisfaction and supported learning in these services. This process can be impeded when experts do not answer questions and/or askers do not have the knowledge and skills needed to evaluate the quality of the answers they receive. Such circumstances may cause learners to construct a faulty knowledge base by applying inaccurate information acquired from online sources. Though site moderators could alleviate this problem by surveying answer quality, their subjective assessments may cause evaluations to be inconsistent. Another potential solution lies in human assessors, though they may also be insufficient due to the large amount of content available on a CQA site. The following study addresses these issues by proposing a framework for automatically assessing answer quality. We accomplish this by integrating different groups of features—personal, community-based, textual, and contextual—to build a classification model and determine what constitutes answer quality. We collected more than 10 million educational answers posted by more than 3 million users on Brainly and 7.7 million answers on Stack Overflow to test this evaluation framework. The experiments conducted on these data sets show that the model using random forest achieves high accuracy in identifying high-quality answers. Findings also indicate that personal and community-based features have more prediction power in assessing answer quality. Additionally, other key metrics such as F1-score and area under ROC curve achieve high values with our approach. The work reported here can be useful in many other contexts that strive to provide automatic quality assessment in a digital repository.