The report presents the results of a longitudinal study that sought to determine if children who participated in Head Start preschool programs demonstrated higher levels of achievement in elementary school, as evidenced by scores on the Stanford Achievement Test in third-grade and first-grade teacher reports. The study involved students who received Head Start services in Broward County, Florida, during 1988-89 and who remained enrolled in county schools through 1993-94, along with 50 first-grade teachers. The study found that although the first-grade teachers indicated that Head Start participation had a positive impact on school readiness, analysis of achievement test scores in third grade indicated no statistically significant differences between former Head Start participants and those not attending Head Start. Two appendices provide a statistical analysis of the achievement test scores. Contains 23 references. (MDM)