Parents in New York City who compete for coveted slots in the most sought-after preschools and kindergartens are often met with ridicule. But what these parents are doing is logical. They recognize something that many leaders — including Mayor Bloomberg — have largely ignored for years: Children learn when they have opportunities to learn, and the richer those opportunities from the very earliest age, the greater the learning.

If you want the right outcome, you need the right inputs.

By the time young children enter kindergarten, education researchers already see a fully developed test-score gap. The children at the top are those most advantaged by their parents’ wealth, having begun their academic development at very early ages. They board an elevator that speeds them to academic success.

Children in middle-class families benefit from some of these resources, but their parents must struggle to try to keep up. Effectively, their parents are able to put them on smoothly operating escalators toward academic attainment goals; but theirs is no express elevator.

Meanwhile, children who are born into poor or lower-income families face enormous disadvantages. They stare up at a steep stairwell, often with broken steps and no hand rails. Although their test scores have increased some over two decades, the relative gap between them and the other groups is still startling high. Nearly two-thirds of black and Latino youth under the age of 18 fall into this group, and, though there are, of course, many exceptions, their talent is being wasted year after year, generation after generation.

This all leads to the predictable, oft-lamented achievement gap — which is powerfully present in New York City, home of some of the richest and some of the poorest people in America, along with plenty in between.

To read the entire op-ed in the New York Daily News, please visit http://www.nydailynews.com/opinion/opportunity-gap-stupid-article-1.1340946.

Carter is professor of education and (by courtesy) of sociology at Stanford University, and Welner is professor of education policy at the University of Colorado-Boulder. They are the co-editors of Closing the Opportunity Gap: What America Must Do to Give All Children an Even Chance.