Mayor Bill de Blasio made a splash with his promise to offer all children classes in computer science over the next decade. But tucked into his education speech on Wednesday was something that may have an immediate, concrete impact: a pledge to hire reading specialists for all the city's elementary schools by fall 2018.

Needless to say, reading is an essential skill. Research shows that children who don't read well by 3rd grade are unlikely to graduate from high school. Unfortunately, New York City has not previously invested in reading specialists—that is, teachers who have a master's degree focused on reading issues.

The number of reading specialists in the New York City schools plummeted from 1,158 in 2002 to 637 in 2013, according to Building Blocks for Better Schools, a report by our parent organization, the Center for New York City Affairs. The reasons for this troubling decline aren't entirely clear, but principals faced with tight budgets often eliminate out-of-classroom positions, such as that of a reading specialist, rather than classroom teachers.

While elementary school teachers are trained to teach reading, reading specialists are trained to identify and treat problems of children who don't make progress despite good classroom instruction. Reading specialists' training is more specialized than a certification in special education. (In fact, special education teachers typically have very limited training in how to teach reading.)

The mayor said the city will begin hiring reading specialists in the spring, with the goal that every elementary school will have one in place by 2018. That's a good start toward ensuring that tens of thousands of children who struggle with reading get a chance to succeed.