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GDO-R & GES Assessment Workshops

Gesell offers two developmental assessments: the comprehensive Gesell Developmental–Revised (GDO-R) and the shorter Gesell Early Screener (GES). Certification is required for the GDO-R. Although certification is not required for the GES, a recommended self-paced GES training is available through our bookstore.

Gesell Assessment System workshops prepare early childhood professionals and parents to understand and better meet the unique needs and abilities of young children through a comprehensive training in the administration and interpretation of Gesell assessment tools.

The Gesell Assessment System uses direct observation, coupled with the unique perspective of parents and educators who know the child, to objectively examine a child’s cognitive, language, motor and social-emotional responses in five strands: Developmental, Letter/Numbers, Language/Comprehension, Visual/Spatial, and Social/Emotional/Adaptive.

Click here to learn more about our Assessment System

A Certificate of Completion is provided for all workshops.

Gesell Assessment System Workshop Options

The Gesell Developmental Observation-Revised Fundamentals: 2½-6-Year-Old Child

Please see calendar for dates and to register.

The Gesell Developmental Observation-Revised (GDO-R) is Gesell's hallmark tool and has since it's development it has been repeatedly validated and improved with the use of strand scoring and performance levels that allow for detailed evaluation in specific domains of growth.

In this workshop participants will learn the fundamentals needed to administer and interpret the results of the Gesell Developmental Observation-Revised (GDO-R) as they relate to a child's neuro-motor, language, cognitive, social, emotional and adaptive responses. Our GDO-R Fundamentals course begins with all the tasks used with children 2½ to 6-year-old, and will all be applicable to those examiners wishing to further their assessment expertise with additional training needed to assess the 6 to 9-year-old child or to assess children virtually, using a web camera.

Specifically, this workshop will address these areas of knowledge and skill needed to responsibly utilize the GDO-R:

  • Foundations of child development for children 2-6 years old
  • Art and science of objective observation inspired by wonder
  • How to administer and then interpret the results of the GDO-R for children 2-6 years old

To meet a variety of learning modalities and preferences, public GDO-R workshops are held online throughout the year and on-site in New Haven at the historic Yale Child Study Center. Private workshops are also available in both online and in-person formats.

Workshop Components

  • In-depth study of developmental behaviors of the 2½ to 6-year-old child
  • Comprehensive overview of developmental age and its implications for learning
  • Demonstration of the administration of the GDO-R with the 2½ to 6-year-old child
  • Hands-on practice of administration of tasks
  • Training and practice on how to interpret and communicate the results of the GDO-R

Workshop Materials Included:

  • GDO-R Examiner's Manual
  • GDO-R Examiner's Script
  • sample forms
Note: Participants may purchase a complete GDO-R assessment kit at 10% off during registration. However, the base registration price does NOT include a complete kit, as many participants work in schools already in possession of a GDO-R kit.

Live/Hybrid Workshop Requirements

Through a guided self-study of an introduction to the curriculum, 2.5 days of live in-depth lectures and discussions with expert assessors and peers, and periodic knowledge check ins, this 4 week hybrid/live workshop provides participants with everything they need to know to administer, score and interpret the GDO-R for children 2.5 - 6 years of age. Please plan for 8-10 hours of online work in the two weeks prior to and 5-10 hours of online work in the two weeks following the 2.5 days of live meetings.

This Live/Hybrid version includes some online content, but mostly presents the core material in the live 2.5 days of meetings. It is best suited for individuals who prefer a live format.



  • Pre-workshop homework including a set of asynchronous online videos to review and online assignments to complete. It is essential to complete this work before attending the live meetings.
  • Live in person workshop meeting dates (2.5 days)
  • Online quiz to complete to demonstrate proficiency and understanding
  • Post-training homework including a set of asynchronous online videos to review and an online evaluation in the two weeks after the live meetings.
  • Full attendance and submission of the above items is necessary to receive a certificate of completion. No certificate of completion will be issued to anyone missing a full live meeting date, or absence for any portion of the live meetings without prior approval from Gesell.
  • Optional: You are invited to submit a recorded assessment with accompanying child recording form, for review by an expert examiner, in the month after the end of the workshop

Online Workshop Requirements

Through a guided self-study of the curriculum, in-depth discussions with expert assessors, collaborative breakout sessions with your peers, and periodic knowledge check ins, this 4 week fully online workshop provides participants with everything they need to know to administer, score and interpret the GDO-R for children 2.5 - 6 years of age. Please plan for 30-40 hours of time over the 4 weeks; 5-10 hours per week.

This Online version provides most of the curriculum through an online self-paced self-study format, with regular opportunities for virtual meetings with trainers. It is best suited for individuals who prefer a self-paced online format, or do not wish to travel.


Spread out over a 4-week training period, there will be:

  • Weekly virtual Zoom meetings, each 1-2 hours
  • A set of asynchronous online videos to review and assignments to complete.
  • Post-training evaluation
  • Attendance and submission of the above items is required to receive a certificate of completion. Missed meetings can be completed, with approval, by reviewing the recording of the meeting. Absence from any portion of synchronous live meetings without prior approval from Gesell will result in forfeit of Certificate of Completion.
  • Optional: You are invited to submit a recorded assessment with accompanying child recording form, for review by an expert examiner, in the month after the end of the workshop

The Gesell Developmental Observation-Revised: 6-9-Year-Old Child Add-On

In this self-paced fully online training, participants will learn to administer the Gesell Developmental Observation-Revised (GDO-R) to the 6- to 9-year-old child and interpret results as they relate to neuro-motor, language, cognitive, social, emotional and adaptive responses. Successful completion of the Gesell Developmental Observation–Revised Fundamentals: 2½-6-Year-Old Child workshop is a prerequisite to purchase this training. That content will not be revisited in depth, but some is required for administration to the 6-9-year-old child.

Specifically, this workshop will address two areas of knowledge and skill needed to responsibly utilize the GDO-R:

  • Foundations of child development for children 6-9 years old
  • How to administer and then interpret the results of the GDO-R for children 6-9 years old

Workshop Materials

  • All participants should have their GDO-R Examiner's Manual with them for the training.
  • Full GDO-R Complete Kit can be on our bookstore
  • Visual III Cards needed for the 6-9 year-old child administration can be purchased on our bookstore.

The Gesell Developmental Observation-Revised Renewal

Gesell strongly recommends examiners renew their certificate of completion every 5 years. New protocols rolled out in 2021 compel us to encourage examiners trained before this date to return as soon as possible. If you were trained in the last 5 years or less, you may renew your certificate of completion by participating in a live or online GDO-R workshop at a reduced rate. Please visit our registration page for details.

Gesell Early Screener (GES) Administration and Scoring Training

The Gesell Early Screener (GES) assists parents, educators, and other professionals in quickly producing a snapshot of a 3 to 6 year old child’s development, compared to other children of the same age. The GES can be administered to a child by persons with varying levels of experience in less than 20 minutes. Unlike the GDO-R, no training is mandated to administer the GES. However, Gesell strongly encourages users to complete a new asynchronous online training to ensure reliability and validity in administration and scoring of the GES.

Purchase GES Administration and Scoring Online Training

Gesell Foundations of Child Development

Dr. Gesell documented what happens to children cognitively, socially, emotionally, and physically during each stage of development, and subsequent research has confirmed his findings. Yet for those of us working with children, their behaviors can often seem mysterious and confusing. In this 45 minute pre-recorded online training study the foundations of child development and the Gesell approach to understanding children at each stage of development from 2 to 6 years of age. This understanding of the ages and stages of child development can assist teachers and parents in setting appropriate expectations for children and support their learning and development.

Beyond Admissions and Placement

A Guide for School Leaders and Teachers in How to Use the Results of the GDO-R and GES to Create Developmentally Appropriate Learning Environments

Free Recorded Webinar

This FREE recorded webinar takes you BEYOND looking at the GDO-R as a placement tool. Find out how the GDO-R can effectively help educators with individualized instruction, differentiated instructional techniques and strategies, and make the classroom environment developmentally appropriate.

View Recorded Webinar Here

Feedback from our workshop participants

Excellent workshop. It is exciting to have a trainer who is so skilled and knowledgeable!

Anonymous

A very informative and useful workshop. I learned a lot about child development and feel comfortable applying what I've learned in a practical setting.

Anonymous

I love the information the Gesell Developmental Observation gives me about each student I have in my classroom! It helps me present learning and activities in a way best suited for each child's developmental stage.

Anonymous

Great training on a fascinating assessment. [Our trainer] was informative and kind about working with the novice assessor, and linked theory to practice. We were also offered plenty of time to experience the materials in a hands-on way. Thanks!

Greta from Washington

This was a great experience and I am eager to keep learning about the GDO-R. I will begin to start practicing!

Amanda from Flourtown

[Our trainer] was PHENOMENAL! The way that she connected with each person and went out of her way to get to know us was delightful. Her perspective of the child and the way that she walked us through each step of the GDO-R was awesome.

Lauren from High Point