Computer tutor versus solving problems by hand: a comparison in statics While computer-based instruction can be used to automate the process of gradinghomework, sometimes its goal is to provide formative feedback to students whilelearning. Formative feedback is often straightforward to provide when students areperforming simple tasks, such as answering multiple-choice questions. In the case ofproblems that are more complex, with many correct pathways to solution, the task ofenabling the computer to follow student work and provide feedback is much morecomplex.Recently, a computer-based tutoring system was devised that focused on truss problemsin statics. This Truss Tutor has a graphical user interface that enables students to solvesuch problems via method of joints or method of sections in a relatively free form way.Furthermore, by intervening at judiciously chosen points that prevent new parts of asolution from building upon errors, Truss Tutor can give feedback to students regardlessof the solution path they take. This is made possible by a cognitive model for solvingtrusses, in particular a set of algorithms for recognizing, for any current correct state,whether any forward step is correct. When an error is detected, feedback is offered thatenables the user to correct that error and continue with the solution. Students in classes ata number of institutions have completed homework assignments using truss Tutor. Byapplying analysis tools used in intelligent tutoring systems, it has been shown that, formany of the sub-skills necessary for solving truss problems, students commit fewer errorswith practice. So, while students using Truss Tutor improve in their use of the tutor itself,it is unknown how using the tutor compares with completing homework problems in thetraditional manner with paper and pencil.In this paper, we describe a study conducted to compare performance on examinations ofstudents who used Truss Tutor to complete their homework assignment with studentswho solved truss problems by hand. The study ...