A Centers for Disease Control and Prevention effort to help identify children with autism and developmental disabilities early so that they can access appropriate supports and services is getting its first-ever update.

The federal agency unveiled revised versions of its developmental milestone checklists this week. The tools are part of the agency’s “Learn the Signs. Act Early.” program, a major initiative to educate families on what to expect from their children at each stage of development.

The new materials diverge substantially from the ones that have been in place since the CDC first launched the checklists in 2004.

While the original version listed capabilities that at least 50% of children at a given age would be able to demonstrate, the updated checklists instead include milestones met by 75% of children at the specified age. The hope is that this change will make it easier to spot children at risk for developmental issues and reduce the likelihood that families and professionals will take a wait-and-see approach if children are missing milestones.

“Average age/50th percentile milestones may be less helpful in identifying when there may be concerns for an individual child because half of children would be expected to attain a milestone at that age and half would not,” said Dr. Jennifer Zubler, a pediatrician who led work on the revised milestone checklists as a contractor for the CDC’s National Center on Birth Defects and Developmental Disabilities. “Using milestones that 75% or more of children would be expected to achieve can help parents and professionals discuss concerns and consider next steps such as performing additional developmental screening to assess a child’s risk for developmental concerns.”

The CDC worked with the American Academy of Pediatrics to put together the new version of the milestone checklists. Zubler led a group of eight experts in early childhood development who conducted a comprehensive review of research and established 11 criteria for the materials. Their report was published this week in the journal Pediatrics.

The update includes additional checklists at ages 15 and 30 months so that there is one available to align with every recommended well-child visit between ages 2 months and 5 years. The materials also feature expanded tips and activities so that caregivers can support development at each stage and there are red flags and warning signs embedded within the milestones.

All of the milestones listed on the checklists can be easily observed in natural settings, CDC officials said, and they’re described in plain language without vague terms like “may,” “can” and “begins.”

The experts behind the changes said they worked to address concerns that having similar milestones across various ages could be confusing. In addition, they sought to show the progression of skills as children age, when possible.

The checklists are intended to be used for developmental monitoring or surveillance and to prompt conversation between families and their pediatricians, CDC officials said.

“Children with autism and other developmental disabilities typically have late onset of multiple milestones across several points in time. When there is consistent delay in achieving these skills, the parents should seek the opinion of qualified professionals, who may perform standardized developmental screening,” said Dr. Paul Lipkin, a developmental pediatrician and researcher at the Kennedy Krieger Institute who helped craft the new milestones.

The CDC said it is in the process of updating its milestone tracker app to reflect the changes in the checklists and a new version of the app should be available in the coming weeks.