Chicago Public Schools is working to improve early literacy outcomes through a multiyear professional development initiative for preK-2 teachers. This initiative--the P-2 Balanced Literacy Initiative--aims to improve literacy instruction by training teachers to balance systematic foundational skills instruction with reading and writing instruction involving rich, complex texts. This study compared the reading achievement of students who attended schools that received the enhanced supports (priority schools) with the reading achievement of students who attended similar schools that received only the initiative's standard supports (nonpriority schools). This Study Snapshot presents key findings from the full study. [For the full report, see ED617588. For the Study Brief, see ED617590. For the appendixes, see ED617591.]