This study investigated the effectiveness of the 'Match it' card sorting activity for evaluating the student teachers' knowledge and understanding of computational thinking (CT) concepts. One hundred forty-six primary student teachers were asked to sort 26 scenarios and words alongside nine images under five main computational concepts: algorithmic thinking, abstraction, decomposition, patterns & generalisation, and evaluation. The study found that the card sorting activity, as a method for assessment, was useful. However, the issues around the design and the content of the current card sorting activity were reported by students, which suggests that further revisions should be made to improve the effectiveness of the tool.