Improving problem decomposition ability in CS1 through explicit guided inquiry-based instruction

CS1 students are often expected to learn to clarify a problem, decompose it into subproblems, solve and test these subproblems as units, and then recompose the tested units into an overarching solution. As other researchers have noted, problem decomposition is often taught only implicitly, but it is an important skill which benefits from both explicit instruction and practice. This paper describes our efforts to improve student problem decomposition ability by utilizing explicit guided inquiry-based instruction in problem decomposition. We applied a problem decomposition rubric adapted from an Association of American Colleges and Universities VALUE rubric to final course projects in two CS1 sections, a CS1 section with explicit instruction on problem decomposition compared against a CS1 section without the explicit instruction. Students in the section with the explicit instruction realized significant gains in problem decomposition ability and also seeming gains in the elective use of unit tests.