The Kindergarten Extended Day (KED) Program provided supplementary instruction for kindergarten pupils tested with the Cooperative Preschool Inventory (CPI) and identified as having educational deficiencies. Pupils in the Elementary Secondary Education Act Title I program attended school for a full day. Academic achievement of pupils relative to KED implementation factors was evaluated and results suggested: (1) students who attended the same session of KED for the entire school year showed higher achievement on the first grade selection instrument, i.e. the California Tests of Basic Skills (CTBS); (2) KED pupils outperformed their non-KED counterparts on the Basic School Skills Inventory (BSSI) and on both subtests of the CTBS; and (3) more than 50% of the pupils had been selected into the KED Program based upon an inappropriate norming table. The majority of the teachers were satisfied with having the CPI as the selection instrument for entry into the KED Program and with adoption of the BSSI as the program's evaluation instrument. (Author/RL)