The primary goal of the Words Work (WW) early literacy initiative was to prepare diverse students to become successful learners in school. Four groups of students were followed over 6 years: students from traditional Head Start (HS) centers, students from augmented HS centers (WW students), students eligible for HS but not enrolled (waitlist or WL), and a random sample of non-Head Start students (NHS). Students received school readiness instruction at approximately 4 years of age, and their performance on standardized tests was followed from 1st grade through 5th grade. WW students significantly outscored HS, WL, and NHS students of similar backgrounds in reading and outscored WL and NHS students in mathematics on 2nd-grade standardized assessments. In addition, WW students were able to maintain their lead through 5th grade in both reading and mathematics. Based on these results, WW is an effective HS enhancement for minimizing the achievement gap often observed between students who may be at risk for academic difficulty and students who are at low risk. (author abstract)