Psychology > Child Cognition, Neuropsychology and Language > Child General Abilities > Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III)

Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III)

Bayley-III packshot

Key information

Examine all the facets of a young child's development. Children are assessed in the five key developmental domains of cognition, language, social-emotional, motor and adaptive behaviour


Nancy Bayley

Publication Year:


Age Range:

1 month to 42 months


Individual - 30 minutes to 90 minutes (depending upon the age of child)

Qualification Code:


Read the full product description

Read more about the Bayley-III UK Validation >

The Bayley Scales of Infant Development (Bayley-III) are recognised internationally as one of the most comprehensive tools to assess children from as young as one month old. With Bayley-III, it is possible to obtain detailed information even from non-verbal children as to their functioning.


Two day Bailey-III training courses available.

> View Training schedule


Children are assessed in the five key developmental domains of cognition, language, social-emotional, motor and adaptive behaviour.

Bayley-III offers significant additions and improvements to the previous editions.

Key features:

  • Core battery of five scales: Three scales administered with child interaction; cognitive, motor, language. Two scales conducted with parent questionnaires; social-emotional, adaptive behaviour
  • Caregiver Report Form - a template for the examiner to provide scores, information on tests given, how child performed and recommendations
  • Behaviour Observation Inventory - separate scale for validating examiner and parent perceptions of the child's responses
  • New norms based on 1,700 children stratified according age, based on the 2000 US Census
  • Ideal for team-testing or multi-disciplinary teams where a professional in each area may assess the child
  • Flexible - can administer one or more domain subtests individually
  • Rolling case for ease of travel  


  • Social-emotional subtest - Authored by one of the USA's leading experts in child development, Stanley Greenspan
  • Adaptive Behaviour subtest - Written by ABAS-II authors Patti L Harrison and Thomas Oakland
  • Caregiver Report - With suggestions to help parents plan for their child
  • Growth Scores and Growth Charts - Chart a child's growth over time
  • Screening Test - A true screener to determine if further testing is necessary


  • Easier to administer, more user-friendly; easy-to-follow record forms, easel-back stimulus book, child-appealing manipulatives and play-based items to facilitate assessment
  • Easier to determine if child performed the target behaviour
  • Simplified scoring rules
  • Extended floor and ceiling - Clinician can more easily identify lower functioning infants and toddlers
  • Improved clinical studies - Special data collected and presented on children with high-incidence clinical diagnoses
  • More parent/caregiver involvement - New test items allow for family input
  • Reduced kit weight and size  

Link between assessment and intervention

Bayley-III identifies infant and toddler strengths and competencies, as well as their weakness. It also provides a valid and reliable measure of a child's abilities, in addition to giving comparison data for children with high-incidence clinical diagnoses. Growth scores can be used to chart intervention progress, and it's useful in programme evaluation, ongoing monitoring of progress and outcome measurement.

Bayley-III UK Validation

Now available, the Bayley-III UK and Ireland Supplement reports the results of the UK and Ireland validation study, general considerations for use of the Bayley lll in the UK and Ireland, and 8 case studies.

A broadly representative sample of 221 children aged around 12 and 24 months in the UK and Ireland was included, taking into account geographic region, gender, age, ethnicity and parental education.

The case studies present developmental history, assessment information, and interpretation of scores for eight children with one of the following conditions: birth asphyxia, prenatal exposure to substance abuse, seizures, speech and language difficulties, Cerebral Palsy, Down Syndrome or PDD.

The EPICure Study is using Bayley-III - click EPICure Study for more information.


Price list

Manual Administration Kits

Complete kit:

Includes administration manual, technical manual, 25 cognitive, language and motor record forms, stimulus book, picture book, 3 sets of manipulables, 25 social-emotional and adaptive behaviour questionnaires, 25 caregiver report forms and administration DVD in a rolling case

Warning - choking hazard for children under 3 years

More info >

ISBN: 9780158027241
£1,521.64 inc VAT


Motor scale record forms, pack of 25
ISBN: 9780158027319
£96.00 inc VAT
Caregiver report forms, pack of 25
ISBN: 9780158027579
£106.80 inc VAT
Cognitive record forms, pack of 25
ISBN: 9780158027647
£114.00 inc VAT
Cognitive, language and motor record forms, pack of 25
ISBN: 9780158027302
£171.60 inc VAT
Language record forms, pack of 25
ISBN: 9780158027654
£114.00 inc VAT
Social-emotional and adaptive behaviour questionnaires, pack of 25
ISBN: 9780158027562
£151.20 inc VAT

Manual Administration Components

Bayley-III Administration DVD
ISBN: 9780158027616
£145.20 inc VAT
Picture book
ISBN: 9780158027340
£28.00 inc VAT
Stimulus book
ISBN: 9780158027333
£337.00 inc VAT

Manipulative Screener Set 1

Includes Bayley-II Set Of 2 Crayons (Group H), Bayley-II Bell (Group G), Bayley-III Spoon, Bayley-III Plastic Glass Clear, Bayley-III Bottle With Lid 33Mm, Bayley-III Oval Shoe Lace, Bayley-III Squeeze Toy, Bayley-III Ziplock Bag 12 X 5, Bayley-II Clr Box-Open End (Group E), Bayley-II Doll (Grp H), Bayley-II Rattle (Grp H), Bayley-II Ring W/ String (Grp I)

Warning - choking hazard for children under 3 years

More info >

ISBN: 9780158027357
£73.20 inc VAT

Manipulative Screener Set 2

Includes Bayley-II Set Of 5 Circles (Group D), Bayley-III Picture Book, Bayley III Wash Cloth - Yellow 50C, Bayley-III Blocks W/Hole Red 4, Bayley-III Blocks Red Set 8, Bayley-III Stepping Path, Bayley-III Story Book, Bayley-III Ziplock Bag 12 X 5, Bayley-II 9 Blue Blocks (Group A), Bayley-II Peg Set (Group B)

Warning - choking hazard for children under 3 years

More info >

ISBN: 9780158027395
£205.20 inc VAT

Manipulative Screener Set 3

Includes Bayley-II Comb (Group H), Bayley-III Pencil With Eraser, Bayley-II Car-Green (Bayleyii/Das/Map), Bayley-III Teddybear Small, Bayley-III Bank, Bayley-III Blocks 4 Small/2 Medium Connecting Blocks, Bayley-III Glitter Bracelet, Bayley-III Lacing Card 5, Bayley-III Memory Cards 3 Set Of 2, Bayley-III Mirror, Bayley-III Puzzle Set 3 (Ice Cream, Cornet Etc), Bayley-III Small Drawstring Bag, Bayley-III Ziplock Bag 12 X 5, Bayley-II 3 Red Blocks (Group A), Bayley-II Small Ball 2 Inch (Group H), Bayley-II Button Sleeve (Group F)

Warning - choking hazard for children under 3 years

More info >

ISBN: 9780158440804
£205.20 inc VAT


Administration manual
ISBN: 9780158027289
£220.00 inc VAT
Technical manual
ISBN: 9780158027296
£220.00 inc VAT

Q-global® Web-based Administration, Scoring and Reporting

Scoring Assistant Software
ISBN: 9780158027623
£302.40 inc VAT

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