In his address to the American Library Association in 2005, then-Senator Barack Obama noted that "literacy is the most basic currency of the knowledge economy." The knowledge economy relies on people who can communicate with others, engage in self-reflection and self-direction, and learn autonomously. In a world where information and technology are moving at ever-increasing rates of speed, our students need to know how to build their knowledge independently and not simply wait passively for someone else to present it to them. The path to building these skills, habits, and dispositions begins with independent reading. Whether in school or out, independent reading builds knowledge. And knowledge, in turn, amplifies reading skills.
Independent Reading Builds Knowledge
Research on the correlation between achievement on standardized tests and reading outside of school is clear—reading volume is associated with academic performance (Anderson, Wilson, and Fielding, 1988). To illustrate this point, consider three hypothetical 5th grade students. The first reads 40 minutes a day on average, meaning she is consuming more than 2.3 million words per year. Her test scores show it; she's in the 90th percentile on standardized assessments. The second—an average student—scores in the 50th percentile. The correlational data show that he reads on average for 12 minutes a day, resulting in about 601,000 words consumed per year, or 1.7 million fewer words than his high-achieving classmate. Of even more concern is the child who reads for only 90 seconds a day on average outside of school. This child is exposed to a deeply impoverished 51,000 words per year (about the same reading volume the first student reads in a week) and scores in the 10th percentile on standardized tests. He will enter high school nearly 7 million words behind his high-achieving classmate. This sobering data is correlational, not causal, but it points to the multiplicative effect of low reading volume across the school years.
Knowledge Builds Independent Reading Ability
Now let's look at the reciprocal: what does knowledge do for reading? Evidence comes from studies like this one done with 7th graders. Students were sorted into four groups across two criteria: current reading level and baseball knowledge. After reading an informational passage about baseball, they were assessed on their comprehension and recall of what they had read. To no one's surprise, those who were strong readers and possessed high knowledge of baseball scored at the most proficient. But to everyone's surprise, the students with lower reading skills but high levels of baseball knowledge performed at comparable levels. In fact, they outperformed those who had high reading skills but low levels of baseball knowledge (Recht and Leslie, 1988). In other words, prior knowledge had a mediating effect on reading performance. The takeaway from these two iconic studies? Knowledge is acquired through reading and in turn plays an influential role in what is understood when reading.