BUGGY is a system for diagnosing procedural errors in the domain of arithmetic manipulation, specifically subtraction. BUGGY uses diagnostic modelling based on procedural networks. A procedural network for a particular skill breaks the skill down into sub procedures and sub goals. A diagnostic model of a student reflects the student’s mastery of a skill in terms of which sub skills are known correctly and which are not.
BUGGY presents to students a series of subtraction exercises. The procedural network for subtraction is used to answer the same questions and the answers generated compared to those produced by the student. If the students answers are incorrect the procedural network is changed to introduce a buggy sub skill. This repeats until the students answers are predicted by the procedural network. If the student consistently makes the same mistakes, errors in application of the subskill generating the mistake are attributed to the student.
A tutoring system IDEBUGGY was developed based on BUGGY. The catalogue of buggy sub skills used by IDEBUGGY was developed by enumerating the bugs present in a database of student tutor interactions.
Authored by Serengul Smith
E-mail to:
serengul1@mdx.ac.uk
School of Computing Science Middlesex University
Revised: September 1998