A considerable number of measures for the evaluation of anxiety in childhood and adolescence are available, most of them developed over the last 20 years. Yet, the selection of measures that best meets the needs and characteristics of a given child can be quite a challenging task. It depends not only on the purpose of the assessment and the qualities of the instruments, but also on the assessor's conceptualization of childhood anxiety disorders. In a behavioural approach to anxiety, the aim of the assessment is to identify eliciting stimuli and target behaviours, and the emphasis will be placed on observational techniques and objective records. In a psychoanalytical approach, the assessment will try to elicit intrapsychic conflicts and will rely primarily on unstructured interviews and projective techniques. The aim of the cognitive approach will be to uncover attentional biases and the schemata underlying anxiety manifestations. The evaluation process may include attributional questionnaires and diaries of dysfunctional thoughts.

Whatever one's theoretical view, the assessment strategy also will greatly depend on the child's age, symptom profile, the sources of information available, and the settings where the assessment is to be done. Similarly, the choice of methods for gathering data depends to a great extent on the classification system used in the assessment of anxiety disorders. For instance, structured diagnostic interviews are particularly suited to categorical classification of anxiety disorders, while self-report or problem checklists are more suited to a dimensional approach to classification.