In 2012-2013, the Heising-Simons Foundation funded the Milpitas Unified School District's Early Learning Transitions Model (ELTM) to enhance supports for children and families as they prepare for elementary school. Although the ELTM has many components, one key feature is the integration of a computerized, adaptive assessment--the Children's Progress Academic Assessment (CPAA)--into teachers' practice in preschool classrooms. The CPAA, which assesses literacy and mathematical skills, is intended to complement the Desired Results Development Profile-Preschool (2010) (DRDP-PS, referred to in this report as DRDP), a teacher rating of children's skills that has been used in the district for over 10 years. The addition of the CPAA expands the information available to teachers and parents regarding children's progress. In order to provide information and guidance to the district as it implements the ELTM, the Heising-Simons Foundation engaged Mathematica Policy Research to conduct a formative evaluation in the district's two preschool programs, referred to as child development centers (CDCs). The two CDCs have a total of six preschool classes serving children ages 3 to 5. Both CDCs began using a blended learning model in 2012-2013 that combines teacher-directed instruction and small-group learning with opportunities for children to work independently on computers or tablets. (author abstract)