Convert marks to UMS (uniform marks scale).

With modular exams, students can take a module in different exam sessions.

Modules may vary slightly in difficulty, from one exam session to another.

For example, a mark of 45 in January 2010 may represent the same level of achievement as a mark of 48 in summer 2010. Raw marks are converted to UMS so that both 45 (from January) and 48 (from the summer) have the same value when contributing to an overall grade.