Mayor Bill de Blasio has claimed repeatedly that his expansion of full-day pre-kindergarten would mean thousands of more children would have access to quality programs. On Friday, education officials released data that analyzed how programs are doing in the "quality" department. 

Of the 1,800 sites that offer pre-k, trained observers assessed 1,100 using the Early Childhood Environmental Rating Scale, a nationally known tool for evaluating pre-k programs. The data was collected over the past three years. 

The city found that 77 percent of programs met a threshold of 3.4 out of a scale of 7. The 3.4 benchmark is associated with positive students outcomes like development of language and social skills, education officials said.

Josh Wallack, the deputy chancellor who oversees pre-k, said the data set the baseline for determining how well the city's pre-k programs, which now enroll 68,500 four-year-olds, were performing.  

“I think what we saw here is generally a very strong result," said Wallack. "We have some programs that need more support than others and that’s exactly where we’re directing the support.” 

Observers assessed classrooms with six categories in mind: physical space, including furniture and whether the room is clean and well-maintained; personal care routines, like hygiene practices; support of language development; the variety of activities available; interaction between children and adults; and program structure, such as the daily schedule.

Pre-k sites can expect two different types of assessments over a three-year period — the environmental rating scale and another assessment that looks more closely on the emotional and instructional supports offered to children.

Steve Barnett, who leads the National Institute for Early Education Research at Rutgers University, said the city's findings were in line with early results from New Jersey's Abbott Districts, pre-k programs widely recognized for their high quality. 

“You start with the programs that you have and raise their quality and that takes time," said Barnett.

When asked if 23 percent of programs not reaching a key benchmark of 3.4 on the environmental rating scale was troubling, Barnett said it depended on the programs' trajectory. "If they stay there, they shouldn’t be in business. And we’d like to see the rest of them move up to 5 or better.”

Parents can find data online for each pre-k program. Pre-k enrollment for next year opens Jan. 25.