This longitudinal study examined the effects on children of three kindergarten schedules: half day, alternate day, and full day. A secondary purpose was to examine the relationship between preschool attendance and subsequent school performance. Two additional variables thought to be related to school success were also explored: children's gender, and age at initial kindergarten entry. The study conducted and combined results of three different specific assessments. The first of those studies, initiated in May 1986, a statewide survey of beliefs and practices concerning kindergarten and preschool, obtained data from kindergarten teachers, school superintendents, school district records, and parents of kindergarten children. The second study, initiated in the summer of 1986, was a retrospective analysis of the cumulative records of 8,290 elementary school pupils. The third study, initiated in the fall of 1986, was a prospective longitudinal study of two groups of almost 6,000 elementary school students. The results indicate that children who attended preschool prior to kindergarten experience greater subsequent success in elementary school than those who do not attend. The child who is most likely to succeed in the elementary grades is a girl who attended preschool, turned five in January before kindergarten entrance and attended a full-day kindergarten program. (Contains 24 references.) (AA)