Constraint-based Student Modelling in Probability Story Problems with Scaffolding Techniques


  • Nabila Khodeir Electronics Research Institute
  • Nayer Wanas Electronics Research Institute
  • Hanan Elazhary Electronics Research Institute



Constraint-based modelling, Intelligent tutoring systems, Scaffolding feedback, Scaffolding questions


Constraint-based student modelling (CBM) is an important technique employed in intelligent tutoring systems to model student knowledge to provide relevant assistance. This paper introduces the Math Story Problem Tutor (MAST), a Web-based intelligent tutoring system for probability story problems, which is able to generate problems of different contexts, types and difficulty levels for self-paced learning. Constraints in MAST are specified at a low-level of granularity to allow fine-grained diagnosis of the student error. Furthermore, MAST extends CBM to address errors due to misunderstanding of the narrative story. It can locate and highlight keywords that may have been overlooked or misunderstood leading to an error. This is achieved by utilizing the role of sentences and keywords that are defined through the Natural Language Generation (NLG) methods deployed in the story problem generation. MAST also integrates CBM with scaffolding questions and feedback to provide various forms of help and guidance to the student. This allows the student to discover and correct any errors in his/her solution. MAST has been preliminary evaluated empirically and the results show the potential effectiveness in tutoring students with a decrease in the percentage of violated constraints along the learning curve. Additionally, there is a significant improvement in the results of the post–test exam in comparison to the pre-test exam of the students using MAST in comparison to those relying on the textbook

Author Biographies

Nabila Khodeir, Electronics Research Institute

Informatics Department

Nayer Wanas, Electronics Research Institute

Informatics Department

Hanan Elazhary, Electronics Research Institute

Computers and Systems Department




How to Cite

Khodeir, N., Wanas, N., & Elazhary, H. (2018). Constraint-based Student Modelling in Probability Story Problems with Scaffolding Techniques. International Journal of Emerging Technologies in Learning (iJET), 13(01), pp. 178–205.