Use of developmental milestones in pediatric residency training and practice: time to rethink the meaning of the mean.

Objective: Pediatricians frequently report the use of developmental milestones in monitoring young children's development, despite evidence that use of screening tools improves detection of developmental delays.

Methods: Core texts in the field of pediatrics and developmental-behavioral pediatrics were reviewed for content and presentation on child development. Most texts included and many focused on developmental milestones, many with an emphasis on 50th percentile milestone data. Problems and limitations in the use of 50th percentile milestones to monitor young children's development and to identify children whose development is suspicious for delay, include questionable utility in clinical decision making and the potential to increase parental anxiety.

Results: The recommendation is made to reconsider a focus on 50th percentile milestone data in pediatric training and practice, in favor of measures that have better clinical utility and are more psychometrically sound.

Conclusions: A conceptual approach to the presentation of developmental milestones differentiates the use of the 10th, 50th, and 90th percentiles of age of achievement of skills, based on the clinical purpose of surveillance.