Reading Comprehension: Reading for Learning C E Snow, Harvard Graduate School of Education, Cambridge, MA, USA ã 2010 Elsevier Ltd. All rights reserved. Defining Reading Comprehension The challenge of understanding reading comprehension derives, in part, from the difficulty of defining its borders. Comprehension was defined by the Research and Devel- opment (RAND) Reading Study Group (RRSG, 2002) as ‘‘the process of simultaneously constructing and extract- ing meaning through interaction and engagement with print.’’ This definition was intended to signal the impor- tance of a number of key features of comprehension: the accurate decoding of print, a process of meaning con- struction through which inferences and information not available from the print are incorporated into the mean- ing representation, and active, motivated engagement from the reader. This definition works well for prototypi- cal cases: the 10-year-old laughing while reading a joke book, the 15-year-old engrossed in a science fiction novel, and the 25-year-old being guided by a manual to install and run a new piece of software. The processes that occur during these prototypical comprehension events have been the subject of considerable research (see RRSG, 2002 for more detailed information about those pro- cesses), which has made clear that the success of any reading comprehension event is determined by variation on three dimensions: the text, the reader, and the task, all defined within a sociocultural context. The RRSG char- acterized successful comprehension as what occurs when the demands of the text, the challenges of the task, and the skills and proclivities of the reader are all well aligned, as exemplified by the prototypical cases listed above. Any pair of these dimensions can be the site of a mismatch that causes comprehension to fail and, as is described below, each introduces some ambiguity about where real reading comprehension begins and ends. Texts Consider a candidate text that might be found in a first grade reader: Alex and Ali ran to the swings and jumped on. What constitutes comprehension for this text? At a mini- mum, a mental representation of two individuals moving quickly toward and using some playground equipment should be conjured up, but is the inference that Alex and Ali are probably children part of the comprehension process or does that go beyond basic comprehension? Is it required that the comprehender assign genders to Alex and Ali, or that gender assignment be postponed, recog- nizing that Alex could be short for either Alexandra or Alexander, that Ali could be a boy’s name or a nickname for Alison? If Ali is provisionally classified as a boy, is it part of comprehension processing to infer that he comes from a Muslim family, or is that an inference that goes well beyond basic comprehension? If the reader has, for example, just arrived from China and has never encoun- tered these first names before, has that reader fulfilled expectations with the inference that these are animate creatures – perhaps as likely to be cats as children? Must the reader infer that Alex and Ali actually started swing- ing, or does that go beyond comprehension into the realm of prediction? Does an inference that Alex and Ali were enjoying themselves belong to the realm of comprehend- ing this sentence or comprehending the world? In other words, what is a sufficiently elaborated representation of this simple sentence to qualify as comprehension? The dilemmas posed by considering different levels of processing of this brief text are, of course, greatly expanded if we consider the comprehension of longer and more complex texts, from paragraphs to newspaper reports or scientific articles to entire novels, let alone trying to establish what constitutes comprehension when reading an array of texts – reports of a political speech in right-wing versus left-wing newspapers, or scientific arti- cles reporting conflicting results, or the entire oeuvre of a novelist – in conjunction with one another. At some point between the simple sentence above and the several volumes of Remembrance of Things Past, the definition of comprehension shape-shifts from a simple representation of an event to deep understanding of a worldview, but fixing the boundary between those activities is not easy. Readers Considering students at different points in development also dictates emphasis on different aspects and levels of comprehension, whether one is motivated to design instruction, select assessments, or investigate the underly- ing comprehension processes. For example, researchers and practitioners focused on reading to learn for students in secondary grades must take into account the over- whelmingly important contribution to successful compre- hension of students’ access to relevant background knowledge. Thus, in science, social studies, and math classes, there is often considerable emphasis on ensuring that students know something about a topic (using 413 International Encyclopedia of Education (2010), vol. 5, pp. 413-418