Pre-service teachers are typically concerned with student assessment and view related issues through varied experiences and backgrounds. Understanding how they think about assessment issues within the current educational context helps to better prepare them. In this paper we describe pre-service teachers' thinking about assessment issues, the theories that underlie their thinking, and how it evolves as a result of using an introspective critical approach called the objective knowledge growth framework. The framework combines the diary and the think aloud protocol and brings pre-service teachers to identify initial assessment problems, propose tentative solutions, and challenge their solutions. Thirty-one pre-service teachers took part in this study and received a one hour workshop on the use of the introspective approach to solve their self-identified assessment issues. Brookhart's 'Tensions in Classroom Assessment Theory and Practice' framework was then used to explore the theories at play when pre-service teachers go through their problem solving processes. The participants identified group work, test failure, accommodation, fairness, multiple assessment opportunities, and academic enablers as key areas of concern. Particularly notable in the study, was the greater importance attached by the pre-service teachers to assessment for classroom management, student motivation, and social justice purposes, than to support learning. The analysis of these concerns using Brookhart's framework and of the reasoning about them suggests that the intersection of measurement, psychological, and social theories continues to impact the decision making process regarding assessment.