Another study by researcher Robert Pianta and colleague Megan Stuhlman comes to a similar conclusion as their last: most American schoolchildren aren't getting a lot of good instruction. What many of them do get, according to the the University of Virginia educational psychologist, is a lot of nice. Their teachers are nice, helpful and emotionally supportive.

Both studies, part of a long-term federal study involving 800 first grade classrooms, look for two kinds of interactions between teacher and student: those that support learning and those that support the student as a person and member of the classroom community.

Classrooms were categorized into four major groups. Almost a third of the classrooms were labeled as providing "positive emotional climate, low academic demand." In these classrooms, teachers were warm and did not discipline with threats, but they often failed to prompt students to think harder or to give the kind of illustrations that make facts stick in the mind.

A still substantial but smaller number of classrooms (17 percent) were pegged as "low quality overall," offering little in the way of instructional support or a positive social climate. In the middle were the 28 percent that were deemed "mediocre" in both areas.

Just 23 percent of teachers managed to combine the two sides of a successful classroom, emotional and academic.

Confirming a lot of other research, class size and teachers' years of experience did not predict which classrooms would be categorized as being of "high overall quality."