An Analysis of Middle Grade Teachers' Debugging Pedagogical Content Knowledge.

There is an increasing need for knowledgeable K-12 computer science (CS) teachers. It is necessary to inform teachers how to debug and help their students debug programs. Research has shown that debugging is difficult for novices because the process requires different skills from creating programs and instructing students how to debug can help them acquire these skills. To this end, we developed a CS professional development for middle grade teachers (grades 5th-8th/ages 10-13) that includes lessons on debugging. The teachers completed debugging activities that involved finding bugs in Scratch programs and explaining how they would help their students in debugging. We qualitatively analyzed their responses and found that teachers successfully identified the problem but they struggled to locate it in the code. In considering how they would help students who had such a bug, the teachers often focused on helping the student find a solution for the bug rather than on identifying the problem or its source. Finally, teachers' ability to identify bugs and the pedagogical strategies to engage students in this process differed based on CS teaching experience and prior CS knowledge. This work contributes to our understanding of teachers' debugging abilities and advances our knowledge on how to support teachers in teaching their students how to debug their programs.