From the beginning of the unit, the format and content of the assessment is made clear to the class, Students are required to move coloured counters around their body to represent the movement of molecules in and out of the bloodstream. They can perform as many practice runs as they need and a great deal of peer tutoring goes on. They are not tested until they feel prepared. Even when testing has started and it becomes apparent that there is a significant problem, the teacher will withdraw to allow the group time to work things out and testing will only resume when they are confident in their understanding. This is considered to be different from traditional testing. The students hav a great deal of significantly time invested in their work and greater value should be placed in encouraging them to maximize their understanding than in finding out how well they perform under pressure.