In the past two decades, something extraordinary has happened with very little fanfare: The reading ability of our lowest-performing children has increased significantly. According to the National Assessment of Educational Progress (NAEP), between 1990 and 2012, the scores of nine-year-olds at the tenth and twenty-fifth percentiles increased by roughly two grade levels (about twenty points). For those children, those gains aren’t just impressive—they’re potentially life-changing.
At the same time, there has been a fourteen-point gain (a little more than a grade level) among fourth graders at the fiftieth percentile and a mere six-point gain among those at the seventy-fifth and ninetieth percentiles.
What’s causing this long-term trend of much greater gains among lower-performing students than higher-performing ones? That’s hard to say. There are many plausible explanations, but one that seems likely is that K–2 teachers have simply gotten better at teaching “decoding” (learning to sound out words). Nationwide, there’s been an increased focus on evidence-based practices, including high-profile initiatives like the National Reading Panel report and Reading First. Both stressed that children must be explicitly taught how to decode, and most early reading programs—and, more significantly, teachers—seem to have gotten the message.
But decoding is only the...