“We still don’t know what the child has…”, told me a teacher about the difficulties she was experiencing with a child who demonstrated behavioural problems. That sentence kept me wondering. Gathering information about what the child “has”, i.e., trying to know “his/her” diagnosis, underlies a genuine concern. But are those difficulties due primarily to something he/she “has”? To what extent knowing the diagnosis is essential to plan interventions at home, daycare or kindergarten?