Unlike traditional courses, units of assessment assess student performance during term rather than in a final exam. These courses are usually project-oriented and have a considerable amount of hands-on work. Units of assessment are the closest that the courses in the CST department come to traditional, not exclusively exam-based, courses elsewhere.

Instructors have a considerable freedom in designing the units of assessment. Some of them have take home exams, some have in class assessment combined with project work, and others are completely based on project work. Units with assessment are only offered in the third year and students typically take one unit each in the Michaelmas and Lent terms.