Hi Patricia: The more consistency that exists in a course, the likely assessments and evaluation can occur with a greater likeleness that essential material will taught, at the right level, using the most appropriate resources, leading the most effective student outcomes. In your example, your course material may have been very organized and planned out well, but if the substitute teacher taught something different, than the quality and accuracy of the lesson can be called into question, with the poor performance on the following days quiz as proof that there was some disconnect. Evaluation should be an accurate reflection of what was taught. If lesson material is misssing, then it's not fair to assess something that was not taught or improperly emphasized. Regards, Barry