Key Information


Nancy Bayley, PhD Glen P. Aylward, PhD, ABPP


Bayley™-4 is the most comprehensive assessment tool for determining developmental delays in children.

Age Range:

16 days to 42 months


Paper-and-pencil; Q-global

Scoring Option:

Q-global (web-based); Manual

Completion time:

30 to 70 minutes (depending upon age of child)

Publication date:

September 2019


Subtest level scaled scores, domain level composite scores, percentile ranks, confidence intervals, developmental age equivalents, and growth scale values



Bayley Scales of Infant and Toddler Development™, Fourth Edition (Bayley™-4) assesses infant and toddler development across five scales: Cognitive, Language, Motor, Social–Emotional, and Adaptive Behavior. Assessment of the Cognitive, Language, and Motor domains is accomplished by administering structured items to the child, and engaging the caregiver to support responses where appropriate. The Social-Emotional and Adaptive Behavior scales are administered via caregiver questionnaire which allows them to share their own observations of the child’s abilities

5 Developmental Domains

CognitiveVisual preference, attention, memory, sensorimotor, exploration and manipulation, concept formation

LanguageReceptive and expressive
language subtests
MotorFine motor and gross
motor subtests
Social-EmotionalCommunicating needs, selfregulation
using emotional signals
Adaptive BehaviorListening and understanding,
talking, caring for self, relating
to others, and playing

Top Reasons to Buy the New Bayley-4

Caregiver Involvement

Caregiver responses can be used to support the scoring of certain items

Time Savings

Reduced number of items and improved workflow provides time savings for the
whole assessment

The shortened adaptive behavior content from the Vineland™-3 saves the caregiver significant time

New Content

Content updates were made based on research and user feedback

Improved Psychometric Properties

Updated normative data and clinical studies

Digital delivery option

Bayley-4 will be available on Q-global® via a digital record form with integrated instructions and flexible administration to help navigate the assessment and improve the examiner workflow.


Adjusts the start point based on estimated due date if child was premature


No need for a separate record form or
administration manual

Supports non-linear administration and administering related items

Ease of use

Messaging included to guide establishing basal and meeting discontinue rules

Contains pictorial representation of administration and examples for
complex items

All items in a series can be simultaneously scored based on a single response


A review screen ensures all required data is captured prior to submitting
the assessment

Item score suggestions are provided based on when the timer is stopped or the number of correct responses to trials