T-scores are scores that are relative to a normative group, or the population average. For example, a T-score of 50 means that the participant obtained a score that is considered average for individuals from the normative group of the same sex and age. The normative sample for these measures include 2482 and 1973 children and adolescents for the CPRS and CTRS, respectively (Conners, 1997). Individuals aged 3–17 years were recruited from over 200 schools in over 10 provinces and 45 states in Canada and the US (Conners, 1997). The composition of ethnic groups was similar to our own study population, although it is suggested that the standard norms for the revised Conners’ rating scales are robust to differences in ethnicity (Conners, 1997).
