The goal of this study was to examine how two groups of middle school students' self-efficacy, interest, goal orientation, and prior experience related to evidence of their building upon existing ideas and code in digital artifacts they created using MIT's App Inventor, a computational practice that Brennan and Resnick (2012) identified as "reusing and remixing." Participants included 110 students in a formal computer science education course and 87 students in an after-school computing club. Data sources included a learner profile survey and participants' digital artifacts. Correlational analysis, followed by logistic regression analysis, uncovered significant relationships between self-efficacy, goal orientation, and evidence of participants' code-oriented reusing and remixing their digital artifacts.