The Role of Interviews in Assessing Developmental Disorders

When a child shows signs of a developmental disorder, the journey to diagnosis rarely begins with a brain scan or a blood test. It almost always begins with a conversation. A clinician sits down with a parent, a teacher, or a caregiver and starts asking questions – about milestones, behaviors, patterns, and daily routines. This is the diagnostic interview, and despite how simple it sounds, it remains one of the most powerful tools in the assessment of developmental disorders. Understanding how it works, what it reveals, and where its limits lie is essential for anyone involved in the care or education of children with developmental challenges.

The interview as a diagnostic tool 🔗

The clinical interview is not simply a casual exchange of information. It is a systematic process designed to gather behavioral data from those who know the individual best – parents, teachers, and caregivers – in order to build a comprehensive picture of how a person functions across different settings and over time. As Hawkins noted as early as 1979, the interview stands as one of the primary methods for collecting behavioral data in developmental assessments, a role it continues to hold today.

What makes the interview particularly valuable is its ability to capture information that standardized tests simply cannot. A cognitive assessment might measure a child’s performance on a given day, but an interview with a parent can reveal how that child behaves at home, how they sleep, how they respond to routine changes, and whether certain behaviors have been present since infancy. This longitudinal and contextual richness is irreplaceable.

Structured, semi-structured, and unstructured formats 🔗

Diagnostic interviews exist on a spectrum of formality. Structured interviews follow a fixed script with predetermined questions, ensuring consistency across evaluators. The Autism Diagnostic Interview-Revised (ADI-R), developed by Lord, Rutter, and Le Couteur, is one of the most widely recognized examples. It is a semi-structured caregiver interview that systematically covers three core domains: language and communication, reciprocal social interaction, and restricted or repetitive behaviors. It is conducted by a trained clinician who questions a parent or caregiver familiar with the individual’s developmental history and current behavior, and it can be used for both children and adults with a mental age above 2 years.

Semi-structured interviews provide a framework of key topics while allowing the clinician some flexibility to probe or follow up on responses. Unstructured interviews, by contrast, are more conversational and exploratory, useful in early stages of assessment when the clinician is still forming hypotheses about the individual’s presentation.

Who gets interviewed, and why it matters 🔗

A thorough developmental assessment involves gathering information from multiple informants who observe the individual in different contexts. Parents and primary caregivers provide indispensable longitudinal data – they have observed the child across years and settings and can speak to developmental milestones, early behavioral patterns, and changes over time. Teachers contribute a different kind of insight, particularly regarding how the child functions in structured social and academic environments. Other caregivers, extended family members, or support workers may add further perspectives on behavior in less familiar or more demanding settings.

This multi-informant approach is not just good practice – it is considered essential. Research has consistently shown that different informants provide unique, valid perspectives on a child’s functioning, and that low-to-moderate agreement between informants is actually expected and informative, reflecting genuine context-specific variation in behavior rather than measurement error.

Challenges and biases in the interview process 🔗

Despite their value, interviews are inherently dependent on the accuracy, memory, and objectivity of the people being interviewed. This introduces a range of challenges that clinicians must carefully account for throughout the assessment process.

Recall bias and the limits of retrospective reporting 🔗

Parents are frequently asked to recall developmental milestones and early behavioral signs that may have occurred years ago. This is a genuine challenge. Research on retrospective caregiver reports has documented a phenomenon called “telescoping,” in which caregivers systematically misplace the timing of their child’s developmental milestones – often pulling events closer to the present than they actually occurred. This is particularly pronounced for children who are older or who have lower verbal abilities. Clinicians are advised to use anchor points such as birthdays or family events to improve the accuracy of recalled information.

More generally, retrospective reports from caregivers may be subject to bias due to the suggestibility of the interviewee or simple errors in recall. While parents tend to be reliable reporters of gross motor milestones, their recall of early language milestones is notably less accurate – a significant limitation given that language development is a key diagnostic criterion for many developmental disorders.

Social desirability and expectation effects 🔗

Informants do not always report what they observe; they sometimes report what they think they are expected to say, or what they feel comfortable disclosing. Social desirability bias can cause caregivers to minimize challenging behaviors due to stigma, guilt, or fear of judgment. Conversely, parents who have already read extensively about a specific diagnosis may over-report symptoms they believe are diagnostically relevant, a form of expectation effect that can skew the clinical picture.

Assessments in populations with intellectual disabilities are particularly susceptible to this kind of distortion. Because individuals with significant intellectual disability may not be able to verbally add to, correct, or confirm information provided by caregivers, clinicians must rely heavily on proxy reports – and those reports carry all the attendant risks of subjective interpretation. Behaviors may be misattributed to the underlying developmental condition rather than being recognized as a separate mental health concern, a phenomenon sometimes called diagnostic overshadowing.

The self-report gap in individuals with intellectual disabilities 🔗

In typical adult psychiatric assessments, the individual being evaluated is the primary informant. In developmental disorder assessments, particularly for those with significant intellectual disability, this is often not possible. Individuals with severe intellectual disability may lack the verbal capacity or self-awareness to accurately describe their own behavioral or emotional states. This creates a fundamental asymmetry in the assessment process: the person being assessed is largely absent from their own diagnostic narrative. Clinicians must therefore be especially rigorous about cross-checking interview data against other sources of evidence, and be alert to the ways in which caregiver perspectives – however well-intentioned – may not fully represent the individual’s actual experience.

Cultural and contextual influences 🔗

Cultural background shapes what behaviors caregivers notice, how they interpret them, and whether they consider them worth reporting. A behavior that is seen as problematic in one cultural context may be considered typical or even desirable in another. Assessment frameworks that fail to account for the cultural lens of the interviewee risk producing skewed diagnostic conclusions. Clinicians are trained to evaluate reported behaviors in the context of the individual’s cultural and family environment, rather than applying a single universal norm.

Complementary techniques: behavioral checklists 🔗

Given the limitations of interview data, comprehensive developmental assessments almost always incorporate additional tools – most importantly, standardized behavioral checklists and rating scales. These instruments serve as a critical complement to the interview, adding structure, objectivity, and quantitative benchmarks to what is otherwise a largely narrative process.

What checklists add to the picture 🔗

Behavioral checklists offer several specific advantages. First, they provide normative data – scores that can be compared to age-matched peers – allowing clinicians to determine whether a particular pattern of behavior is statistically unusual. Second, by systematically covering a wide range of behaviors, they help reduce the recency bias that often affects interview responses, where recent or dramatic events tend to overshadow more subtle patterns. Third, many scales offer parallel versions for different informants – parents, teachers, and sometimes the individual themselves – making cross-informant comparisons straightforward and structured.

The Child Behavior Checklist (CBCL) is one of the most widely used parent-report tools for assessing emotional and behavioral problems in children. It covers eight syndrome scales including social problems, thought problems, attention problems, and aggressive behavior, and has been validated across thousands of studies. Research has shown that children with autism spectrum disorder consistently display elevated scores on the Social Problems, Thought Problems, and Attention Problems scales, which can serve as a useful prompt for further diagnostic evaluation.

For adaptive behavior specifically – the ability to meet the demands of everyday life – the Vineland Adaptive Behavior Scales (VABS) are the most widely used measure. The Vineland assesses communication, daily living skills, socialization, and motor skills through a semi-structured caregiver interview or rating form. It is a key instrument in the diagnosis of intellectual disability, autism, and related developmental delays, and is explicitly recognized by both the American Association on Intellectual and Developmental Disabilities and DSM-5 as meeting the standards required for diagnosing intellectual disability.

Checklists do not replace interviews – they complete them 🔗

It is worth being clear about what checklists cannot do. They do not capture the kind of narrative detail, developmental history, or contextual information that an interview produces. Studies comparing informant rating scales with direct observation have found that while parent ratings and standardized reports tend to agree at a general level, agreement drops considerably when the analysis moves to specific behavioral topographies. This means checklists and interviews each capture something the other misses – making both necessary components of a thorough assessment rather than alternatives to each other.

The best-practice model in developmental disorder assessment is therefore a multi-method, multi-informant approach: structured or semi-structured interviews with key informants, supplemented by standardized behavioral rating scales, direct observation of the individual, and where possible, formal cognitive and developmental testing. No single tool is sufficient on its own. The interview remains the cornerstone of this process – the starting point for constructing the clinical narrative – but its conclusions must always be tested against data gathered through other means.

What do you think? If a parent and a teacher give very different accounts of the same child’s behavior during assessment, how should a clinician decide which account carries more diagnostic weight? And given the limitations of retrospective recall, is there a strong case for collecting more developmental data prospectively – before concerns even arise?

References

1. https://pubmed.ncbi.nlm.nih.gov/7814313/
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5. https://pmc.ncbi.nlm.nih.gov/articles/PMC11059834/
6. https://www.leadersproject.org/2012/11/28/the-consequences-of-bias/
7. https://pmc.ncbi.nlm.nih.gov/articles/PMC3362998/
8. https://www.sralab.org/rehabilitation-measures/vineland-adaptive-behavior-scales