More than 1.5 million American children are enrolled in publicly funded preschool programs, and the number is growing every year as states and cities allocate funding to boost children’s school readiness and support working parents. But the quality of those programs is incredibly varied despite the fact that experts know more than ever before about the kinds of classrooms that ensure children are academically, socially, and emotionally well-adjusted. There is a big debate raging about the educational needs of little children, one that is entangled with larger questions about poverty and equity. The debate doesn’t center on whether the United States should support disadvantaged children to get ready for school, but how. Do children at risk of falling on the losing end of achievement gaps need a strict focus on the basics, or do they need the more holistic, learn-to-love-learning approach that middle-class parents tend to clamor for? It’s a thorny question, and parents and teachers sometimes fall on surprising sides of the spectrum.

In the two years I spent visiting preschool classrooms, I saw a huge range in quality and instructional approaches. There were programs in poor neighborhoods where children delighted in learning vocabulary from field trips to historical sites, and classrooms in affluent places that were fancier than some colleges. The programs that left me with the starkest impression were those that used a strict, basics-only approach, where teachers lectured at children and the children parroted back what they said. These programs are more common in low-income neighborhoods than they are in more-affluent ones, according to research and my own reporting. At the D.C. school where I met the children playing with water, 4-year-olds spent much of the day in groups of three or four, listening to a lesson tailored to their skills as measured by a standardized test. At the end of each lesson, they had to take a three-question quiz about what they had learned. If they all “passed,” they would complete a new lesson the next day; if one of them “failed,” a teacher explained, they all had to repeat the same lesson the next day. Five times a year, the children take a standardized test to measure their progress and assess what they know, using computerized tasks and teacher-dictated questions. I was struck more by what the children didn’t know. I observed one little boy as he hesitantly guessed the answers to a three-question quiz about rhyming, and then walked away relieved but clearly confused.

Low-income preschoolers and children of color are more likely to get the kind of skill-and-drill instruction I saw at that school than are their higher-income peers, according to a study by Rachel Valentino, an education-policy researcher from Stanford. Across programs in 11 states, including New Jersey, Georgia, and Wisconsin, African American and poor children experienced more time in didactic instruction than white and non-poor children, while white and non-poor children spent more time in interactive instruction. Teachers had less back-and-forth or “elaborated” conversations with black students than they did with their white ones. African American, Hispanic, and poor children spent more time doing individual tasks like worksheets and computer time and spent less time on free-choice activities. They also spent more time on basics like letters and sounds, and even on fundamental things like toileting and cleanup.