In this study we extend our prior exploration focused on the extent to which middle school teachers appropriately identified proportional situations and whether there were relationships between attributes of the teachers and their ability to identify proportional situations. For this study, we analyzed both a larger dataset (n = 32) and two dynamic scenarios in which participants were asked to consider aspects of the relationship shown in the diagrams. We found teachers who were correctly able to discern that a situation was not proportional were more likely to use important knowledge resources to evaluate the tasks. [For complete proceedings, see ED581294.]