CDC’s developmental milestone checklists are communication tools intended to encourage ongoing conversations between families and professionals. The checklists also help identify the need for additional screening (between universal screening ages, as needed) when there is a potential developmental concern. Milestones are just one part of these communication tools. 

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1. The developmental milestones included on CDC’s milestone checklists are not developmental guidelines or standards for children’s development. They should not be used as screening or diagnostic tools to detect developmental delays. If developmental concerns are noted, the next steps are screening and evaluation with formal tools or referral for services.

2. CDC’s developmental milestones should not be used to establish medical necessity for the initiation or continuation of services. They also should not be used as justification to discontinue services.

3. A published, peer-reviewed literature review conducted in 2019 informed the placement of the developmental milestones included on CDC’s milestones checklist. That evidence, along with their expert clinical judgement helped guide the authors on what well-child visit age to place the evidence-informed milestones so that about 75% or moreof children would be expected to exhibit it. This process is described, and the evidence reviewed listed, in the paper, Evidence-Informed Milestones for Developmental Surveillance Tools | Pediatrics | American Academy of Pediatrics (aap.org).

4. Milestones were placed at ages by which at least 75% of children would be expected to exhibit them, in an effort to make even one missing milestone more “actionable” (likely to prompt screening and possible referral). With a milestone at 50%, half of all children would still reasonably be expected to have not yet achieved it. This change is intended to reduce the “wait and see” approach often taken when a child is missing an average age milestone.

5. CDC’s milestone checklists do not contain all possible milestones children might exhibit. Inclusion or exclusion of a milestone was based on limited available published evidence. Inclusion or exclusion is not a reflection of the significance of a particular milestone in a child’s development.

6. The milestones and open-ended questions underwent cognitive testing (testing for understanding and relatability) in English and Spanish with parents of young children from different racial/ethnic backgrounds, income levels, and education levels across the country. These steps were taken to ensure the milestones were easily understood and the examples provided were relevant and helpful. The language used in the final checklists reflects a 5th– to 7th-grade reading level.

7. Revised developmental milestone checklists and other Learn the Signs. Act Early. materials were made available in February 2022. These revisions are intended to better support ongoing conversations about children’s development between families and professionals. They also help promote early identification of and action on potential developmental concerns so that children and families can get the early services and support they may need.