What Is a Diagnostic Evaluation?

A diagnostic evaluation assesses various areas of development to gain a “full picture” of a child’s development and learning style. The information gathered in the diagnostic evaluation can also help determine services that might be beneficial to support the child’s development, such as speech therapy or applied behavior analysis (ABA) therapy.

Some of the areas that might be assessed include:

  • Body structure and function: strengths and weaknesses associated with certain developmental disorders
  • Developmental domains: including hearing loss and some genetic syndromes
  • Activities of daily life: including the ability to participate in everyday situations
  • Quality of life: including personal and environmental factors that either aid or impede the daily life of the individual

The evaluation process
Diagnostic evaluations given by a clinical psychologist generally follow a 3-4 step process. The exact elements of these steps can vary from practice to practice, but most clinicians will follow a process similar to the one below:

  • Review of records and history: Before a diagnostic evaluation, a clinician will ask for any past records of the child’s history of health and behavior that are deemed relevant. These may include medical records, previous assessments by other clinicians, and preliminary developmental milestone screenings done by a child’s pediatrician. The clinician will review these documents prior to the first appointment to give themself a background on the child’s health and behavior.
  • Parent report or interview: Prior to a first meeting, a clinician may ask the child’s parents, caregivers, and teachers to fill out questionnaires detailing aspects of their child’s behavior and daily life. These questionnaires are a great way for a clinician to get to know the child from the people who know them best. These questionnaires are also an important part of the diagnostic process as they provide the clinician with information about a child’s adaptive behavior, or everyday life skills, that would be difficult to observe in a clinical setting. A clinician may also wish to meet with parents for an informational interview during this part of the process, in order to give parents a chance to ask questions and familiarize themselves with the way the evaluation will be conducted for their child.
  • Child observation and assessment: For this part of the evaluation, the clinician will observe the child and administer standardized test assessments designed for the diagnostic evaluation of developmental disorders. The specific tests can vary depending on the clinician and the child’s needs, but the most common categories tested are as follows:
    • Cognitive assessment: used for language skills and problem solving, as well as an IQ test
    • Adaptive behavior assessment: tests a child’s daily life skills and abilities
    • Autism-specific assessment: this is used when testing for ASD, and tests social communication skills and repetitive behavior tendencies.
    • All information gathered during the child observation will be used to support and inform a diagnosis or result. Child observation can also provide valuable insight to the clinician on the best path for treatment to recommend to a family following a diagnostic evaluation.
  • Feedback session: Once a clinician has reviewed the information from the evaluation, they will meet with parents to discuss the results of the testing and provide their diagnosis. During this feedback session parents may ask questions and request resources. At this time clinicians will also provide the family with their recommendations for treatment. Parents will also be provided with the clinician’s formal written report either during the feedback meeting, or shortly afterwards.


“Autism Spectrum Disorder: Assessment.” Spectrum Disorder: Assessment, ASHA, www.asha.org/PRPSpecificTopic.aspx?folderid=8589935303§ion=Assessment.

“A Parent’s Guide to Psychological Evaluations for ASD.” Vanderbilt Kennedy Center, Vanderbilt Consortium Lend, 2010, https://vkc.mc.vanderbilt.edu/assets/files/resources/psycheval.pdf.

Kacinski, Anna. “8 Things You Should Know about the Diagnostic Evaluation Process for Autism Spectrum Disorder.” Alternative Behavior Strategies, Alternative Behavior Strategies, 30 Oct. 2018, https://alternativebehaviorstrategies.com/8-things-you-should-know-about-the-diagnostic-evaluation-process-for-autism-spectrum-disorder/.