If students do not have an opportunity to make their thinking visible, how are you going to assess if they understand a concept? Thinking can be made visible in a variety of ways, however, visible thinking is different from a basic checking for understanding. When a student has to make his thinking visible the student is showing how he understands a concept and not just stating whether or not he thinks he understood the content. The drawback to thinking routines is that they can take time. The value of them is that they give teachers real and timely formative information about how students understand a concept.