Bayley Scales of Infant and Toddler Development | Fourth Edition
Bayley-4
Bayley™-4 is the most comprehensive assessment tool for determining developmental delays in children.- Age range:
-
16 days to 42 months
- Publication date:
- September 2019
- Qualification level:
-
B
- Completion time:
-
30 to 70 minutes (depending upon age of child)
- Administration:
-
Paper-and-pencil; Q-global
- Scores/Interpretation:
-
Subtest level scaled scores, domain level composite scores, percentile ranks, confidence intervals, developmental age equivalents, and growth scale values
- Scoring options:
-
Q-global (web-based); Manual
- Other languages:
- Simplified Chinese
- Telepractice:
- Guidance on using this test in your telepractice
In each episode, you’ll meet someone who makes a profound difference in other people’s wellbeing every single day.
Professionals have relied on the Bayley Scales of Infant and Toddler Development™ for more than 50 years to identify potential delays in children and get interventions in place early on.
Benefits
- Use caregiver responses to support the scoring of certain items.
- Determine the need for further in-depth assessment.
- Administer one or more domain subtests individually.
- Save significant time through shortened adaptive behavior content from Vineland 3.
Features
The new version of the Bayley Scales of Infant and Toddler Development features:
- Digital delivery option via Q-global combines the record form and administration manual, which allows greater flexibility, ease of use and improved accuracy.
- Content updates made based on research and user feedback.
- Updated normative data and clinical studies.
- Includes complimentary Introductory Online Training

Bayley™-III vs. Bayley™-4: What’s changed?
Administration & Scoring
| Bayley-III |
- Flexible administration with Series Items noted on the record form
- Motor response items embedded in the record form
- Dichotomous scoring approach (i.e., 1, 0)
- Flexible administration with Series Items and Related Items identified on the record form and supported via digital administration
- Motor response items in a separate Motor Response booklet • Structured caregiver questions to support administration on relevant items
- Polytomous scoring approach (i.e., 2, 1, 0)
Content Updates
| Bayley-III | Bayley-4 |
|
|
Norms and Clinical Studies
| Bayley-III | Bayley-4 |
|
|
Administration Time
| Bayley-III | Bayley-4 |
|
|
Digital Delivery
| Bayley-III | Bayley-4 |
|
|
Kits, components, and pricing
-
Materials are available to purchase separately; however, it is more expensive to upgrade this way than to purchase a new kit, i.e. the items required to upgrade would be:
- Bayley-4 Administration Manual (paper or digital)
- Bayley-4 Technical Manual (paper or digital)
- Bayley-4 Stimulus Book (paper)
- New Manipulatives (small set of disks (3); cat puzzle; memory cards; ducks; pennies and penny bank; large disks (6); small car)
- For manual administration and scoring:
- Cognitive, Language, and Motor Forms, and Motor Response Booklets (pkg of 25 of each)
- Social-Emotional & Adaptive Behavior Record Forms (pkg 25)
- Caregiver Report (pkg of 25)
- For digital administration and scoring:
- Q-global: Cognitive, Language and Motor administration, scoring & report and Motor Response Booklets
- Q-global: Social-Emotional & Adaptive Behavior administration, scoring and report
-
The Scoring-Subscriptions provide a digital scoring option for paper-based administration. They allow manual entry of raw data to generate scores and reports.
The Cognitive, Language and Motor Administration, Scoring and Report is used for the on-screen administration of these domains, and is a digital version of the Cognitive, Language, and Motor Record Form. This is for the Examiner to use and complete.
The Social-Emotional & Adaptive Behavior Administration, Scoring and Report is a digital equivalent of the Social-Emotional & Adaptive Behavior record form. This is a caregiver questionnaire which can be emailed to the caregiver with a secure link to complete or can be completed within your office on an internet enabled device.
Content
-
For certain questions a caregiver response is possible for scoring the item, see the example below:
Ask caregiver, "When you say the name of a familiar object, does [insert child's name] look at the object you named often, not often, or not at all?"
Score
2 points, Often
1 point, Not often
0 points, Not at all -
The Caregiver Question should not be used in every item where it is an option or where a score of '2' is not assigned. The intent of the caregiver questions is not to optimize scores as much as possible. Rather, they are to be used when a response is ambiguous, the child is not cooperative, or if the behavior may have a greater likelihood of occurring in familiar surroundings. Frequent discrepancies between what is observed during testing and the caregiver question responses raises questions regarding the validity of Caregiver Question scores, and clinical judgement should guide interpretation.
-
Bayley-4 is not currently available in Spanish.
-
Prematurity is considered 36 weeks 6 days or less gestation. This is what is meant by "36 weeks or less gestation" on page 27 of the Bayley-4 administration manual.
Digital Administration and Scoring
-
This is possible and depends on how the account is set up. Some Q-global users intentionally set up their accounts so that all their team members can view their examinees as a group (rather than just the ones they have entered). Of course, an account can also be setup so that users can only see their own examinees. This is a choice made when the account is set up.
If an account is set-up so that it is in the same hierarchy as other accounts, then the examinee record can be moved from one account to another for other disciplines to enter and score their section. Examinee records cannot be moved to an account within a separate entity / hierarchy.
-
The digital administration of Bayley-4 is a digital record form, the child does not interact with the administration device (e.g. tablet/laptop), the administration guidelines between paper and digital are the same.
As part of the Bayley-4 validation we conducted a study comparing performance on Bayley-III (paper scoring) and Bayley-4 (digital scoring). The data indicates that the children's performance on the two tests are similar (no significant difference).
-
The digital administration uses Q-global and combines the record form and administration manual for more streamlined administration. It is optimized for the screen-size of a tablet (e.g. iPad) or larger. Although it will work on a smart phone it will not be a good user experience. Q-global can be used on any device that has internet. You cannot use Q-global without internet access.
The Social-Emotional & Adaptive Behavior questionnaires can be administered remotely via a secure email link.
-
It is recommended to adjust for prematurity up to 24 chronological months, however, the platform will allow you to adjust beyond this age. There is on-screen text advising the recommended ages for adjusting.
-
Growth Scale Values are included in Bayley-4. These are useful for re-evaluation purposes and are available for both paper and digital administration.
For paper administration statistical significance is also available to evaluate change in Growth Score Values between two administrations.
-
Information is continually backed up in Q-global, if a connection drops during administration then any data entered will have been saved. Once you're able to reconnect, the session will continue from where you left off.
-
Offline administration is not available currently. The back-up option is to use paper administration, and enter the scores manually, a subscription version of Bayley-4 on Q-global to facilitate this.
-
The Social-Emotional & Adaptive Behavior Questionnaire can be administered remotely. Guidance to support telepractice administration of Bayley-4, including the Cognitive, Language and Motor scales is available here
Psychometrics
-
Growth scale values (GSVs) provide a score metric that does not involve age-based comparisons. Their purpose is for tracking performance across repeated test administrations. If a raw score increases upon a repeat administration, the GSV also increases.
The GSVs have a mean of 500 and a SD of 25. Because of their construction, GSVs cannot be meaningfully compared between subtests or subdomains. GSVs enable the measurement of an individual child's progress or improvement in an absolute sense. Although the normative scaled scores provide information about a child relative to his or her peers at a given time and may show little change over time, the GSV can provide an ability to estimate independent of one's peers and can track growth over time.
-
The normative sample was aligned with the latest US census data and included children from culturally and linguistically diverse backgrounds including bilingual children.
-
A Social-Emotional Age Equivalent table is also available in the Q-global Resource Library. For those without access to Q-global, please contact customer support to request a cop
Training
-
Please see the welcome letter provided with your kit. Alternately, for digital users, details are available in the Q-global resource library for Bayley-4. You can also view training options under the training tab on the Bayley-4 webpage.
Bayley-4 in Simplified Chinese
If you are interested in Bayley-4 in Simplified Chinese language please reach out to our partners
Program items
Bayley-4 Complete Kit (Print); Bayley-4 Consumable Combos Pack

