“Milestone checklists provide a framework to parents and providers to help see when formal testing for a possible delay may be needed,” says Dr. Jennifer Cross, an attending pediatrician and a developmental and behavioral pediatrics expert at NewYork-Presbyterian Komansky Children’s Hospital. “Based on 15 years of evaluating the previous CDC checklists, a number of studies, and clinical experiences, clinicians and researchers concluded that the checklists were confusing and caused a false sense of security,” she says.
“This was because the ages on the checklist were based on when the ‘typical’ child reached this milestone, or the 50th percentile, which meant that half of all children would not meet the milestone by that specific time,” says Dr. Cross. “The current checklists have been revised to be more helpful, with the decision to move the age levels to those at which 75% of children would have been expected to accomplish a certain milestone. The hope is that parents and clinicians would move more quickly to evaluation and possible intervention for children who had not mastered the milestone outside of the average range.”
In addition to that change, there are also now checklists and proactive tips provided for 15-month-old and 30-month-old children, and the lists for all ages feature anticipated actions, physical movements, and emotional responses. The AAP notes that some milestones have been moved to different ages, and some have been removed from the lists altogether.