A Principled Approach to Designing a Computational Thinking Practices Assessment for Early Grades.

In today's increasingly digital world, it is critical that all students learn to think computationally from an early age. Assessments of Computational Thinking (CT) are essential for capturing information about student learning and challenges. Several existing K-12 CT assessments focus on concepts like variables, iterations and conditionals without emphasizing practices like algorithmic thinking, reusing and remixing, and debugging. In this paper, we discuss the development of and results from a validated CT Practices assessment for 4th-6th grade students. The assessment tasks are multilingual, shifting the focus to CT practices, and making the assessment useful for students using different CS curricula and different programming languages. Results from an implementation of the assessment with about 15000 upper elementary students in Hong Kong indicate challenges with algorithm comparison given constraints, deciding when code can be reused, and choosing debugging test cases. These results point to the utility of our assessment as a curricular tool and the need for emphasizing CT practices in future curricular initiatives and teacher professional development.