How to use the Bayley Scales of Infant and Toddler Development.

The Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III) is a gold standard series of behavioural assessments used by clinicians and researchers to assess the developmental functioning of young children. The rigorous psychometric properties of the tool are attributed to the carefully standardised normative sample and quantitative scoring system. It is a common end-point assessment used in neonatal trials and is routinely used in a clinical setting to assess the development of children at risk of delay. Incidence of developmental delay is higher in clinical populations such as those born preterm or with complications such as neonatal encephalopathy. Early identification of delay is critical as early intervention is most effective in minimising impairment; therefore, routine assessment of developmental outcomes is recommended, particularly among high-risk populations. © Author(s) (or their employer(s)) 2021. No commercial re-use. See rights and permissions. Published by BMJ.