Automatic Identification of Errors in Multi-step Answers to Algebra Questions

This paper presents a system that automatically identifies errors made by students in answering algebra questions that require multiple steps. The types of algebra questions we consider include linear equations with fractions and quadratic equations. We have already developed a system that is capable of grading multi-step answers to the aforementioned two types of questions and awarding full/partial credit according to a marking scheme. The error identification module works on top of this previous system. It was evaluated using data from two sources: government schools and a tuition class in Sri Lanka. The mistakes identified by the system were compared against feedback by two independent teachers. The results showed that the system identified the student mistakes with more than 85% accuracy for both types of questions.