The SDQ (Goodman, 2001) consists of 25 items describing positive and
negative attributes of children that can be allocated to 5 subscales of which hyperactivity/inattention
(which consists of 5 items: “Restless, overactive, cannot stay
still for long,” “Constantly fidgeting and squirming,” “Easily distracted, concentration
wanders,” “Thinks things out before acting,” and “Sees tasks through to the
end, good attention span,” of which the latter two are of course reversed items) was
considered as most relevant regarding the content of the study. Other subscales
refer to other difficulties such as emotional problems, conduct problems, and peer
problems, and strengths (i.e., prosocial behaviour). Items have to be scored on
a 3-point scale with 0 = not true, 1 = somewhat true, and 2 = certainly true.
Subscale scores can be computed by summing ratings on relevant items (after
recoding reversed items).
As mentioned earlier, all measures were completed by parents, teachers,
and children (in case they were 8 years or older). The self-report rating scales
were identical to the parent/teacher version, except that items were simplified and
rephrased in terms of the child’s perspective