Early intervention (EI) and early childhood special education (ECSE) practitioners participating in the Child Outcomes Summary (COS) process must understand age-expected development, the ages at which children typically acquire different skills. The COS process requires an understanding of the timing and sequences of development that enable children to have positive social relationships (Outcome 1), acquire and use knowledge and skills (Outcome 2), and take action to meet their needs (Outcome 3). When determining COS ratings, COS team members need to consider the child’s functioning relative to what is expected for his or her chronological age. This is referred to as age anchoring. This resource provides answers to commonly asked questions about age anchoring as it applies to the COS process. It is designed as a reference for practitioners, as well as supervisors, coaches, and professional development staffs.