Over the years I had learned that it is not a good idea to take a child by surprise. Unpredictability and the unknown make everyone feel anxious and, therefore, less able to process information accurately. Also, and importantly for clinical evaluation, the more anxious someone is the harder it is for them to accurately recall and describe their feelings, thoughts and history. But most critically, when a child is anxious it is much more difficult to form a positive relationship, the true vehicle for all therapeutic change.
I had learned the power of first impressions, as well. I could get a much better sense of a child's prognosis if he had a favorable or at least a neutral first impression of me. So rather than just start asking questions of an unsuspecting and usually frightened and disoriented child, I'd found it was best to give him a chance to meet me first. We'd have a brief humorous or engaging conversation, I'd let him size me up a little, provide a clear, simple explanation of what I wanted to learn from him, and then leave him alone for a while to process that information. I'd assure him that he was in control.