It is common to watch closely the extent to which students are acquiring basic skills in reading, mathematics, and writing, but equally compelling and often neglected is the question of whether students are really understanding what they are expected to be learning. Deficits of comprehension are common and often very subtle. They have the potential to make school uninteresting and intimidating for many students.

There are multiple targets for understanding in education. Kids need to grasp ideas, issues, concepts, rules, processes, and even skills (it is possible, after all, to apply a skill without really understanding it). Different students reveal different levels of comprehension. Some may have only a minimal understanding of the ideas under consideration in a social studies class, while others can analyze and see their implications with relative ease. Children who are deficient in their understanding may become bored and inattentive during class or they may simply over-rely on memory and try to store and regurgitate material they've never really been able to interpret. That sometimes works, but it's hardly a satisfying way to become educated!

Some students reveal weak comprehension monitoring; they don't understand whether or not they understand. They may think (or want to think) they comprehend some ideas but, in reality, their understanding is superficial or even non-existent.

There are many possible reasons why a child may reveal a comprehension deficit in school. First and most common are various weaknesses of language processing. Two forms are especially frequent. First many students have semantic deficiencies; they have a superficial handle on word meanings. The words they know they know only vaguely, unaware of their connections to other words, their shades of meanings, their broad implications and applications. As kids progress through school, there is a never-ending tidal wave of vocabulary that is often decontextualized (removed from the experience of every day life). There is also a proliferation of technical vocabulary, words like hypotenuse, refraction, and nepotism. These are terms your mom never utters at breakfast, and they can seriously threaten the learning of kids with semantic gaps. Other students endure language problems at the sentence level; syntax or word order doesn't register or ring meaningful bells for them. As a result, they are apt to have trouble following directions, interpreting verbal explanations, and understanding what they read. Sentence comprehension problems are especially common during the elementary school years, and some victims seem to develop attention deficits that are caused by their lack of comprehension. Why keep listening when you can't understand?

Some students are plagued by nonverbal comprehension gaps. They have problems visualizing phenomena. It may be hard for them to grapple with the distinction between a rectangle and a parallelogram because they are weak at discerning such spatial differences. They may also have trouble understanding the rotation of planets, the flow of blood through the human circulatory system, and the geographic locations of specific Asian countries. In other words information that requires enhancement without heavy reliance on language may elude such students.

Many kids have trouble forming concepts. Concepts are groups of features that go together and are known collectively by a particular term. The concept of civil rights contains a cluster of identifying features. So do the concepts of acceleration, evaporation, vegetation, and reforestation. Students suffer in their understanding when they are unable to identify the critical features that make up a concept. It is then hard for them to know what is really meant by Liberalism or perimeter when they meet up with such words in a textbook or during a class discussion. They are likely to have trouble citing examples of these concepts and describing how they get applied.

Sometimes memory weaknesses can thwart comprehension. Understanding new information depends in part on attaching it to what you already know. There are students who have limited access to their prior knowledge, so it becomes hard for them to make immediate sense of new inputs. Other students can't hold new information in short-term memory, especially if it arrives at a rapid rate or in extra large chunks. They become disoriented when such information flows and may experience frustration in trying to comply with oral directions, copy from the board, take notes, or comprehend the basic ideas contained in a lecture.

Problems with comprehension are especially common in high school and college. A teenager may insist she "doesn't get" physics or chemistry or political science. Unfortunately few students know much about what understanding entails. They are unaware of the forms of understanding I have mentioned in this essay. This is particularly problematic for students who have trouble understanding, especially those who don't really understand that they're having trouble understanding (that's most of them, I think)! Early in a child's education, we need to be emphasizing the understanding of understanding, fostering what is called "metacognition" in every student. By thinking about thinking while they are thinking, kids can gauge whether or not they understand. They can learn about their own preferred pathways of comprehension. They can figure out how best to represent new information in their minds. Should it be a picture, a verbal description, a diagram, a formula, an example, etc.?

Misunderstanding students are too often misunderstood. We need to be able to identify partial graspers, help them understand themselves, and develop with them the tools they will need to be able to comprehend.