In 1969 Di Lorenzo studied the effects of a year prekindergarten school experience on l,807 low-income children. Again, the majority of the children studied were Black. The study was a true experimental design, with stratified random assignment, in eight school districts in New York. Four of the programs were described as early childhood oriented, four as cognitively oriented. Of the four cognitively oriented programs, one was a Montessori program. Three waves of children were tested on measures including the Stanford-Binet IQ test, the Peabody Picture Vocabulary Test, the Illinois Test of Psycholinguistic Abilities, the Learner Self-Concept Test, and the Metropolitan Readiness Test, at the beginning and end of prekindergarten, kindergarten, and first grade years.