title: Using the Conners' Teacher Rating Scale-Revised in school children referred for assessment.
abstract: OBJECTIVE
  Predictive validity of the Conners' Teacher Rating Scale-Revised (CTRS-R) was evaluated against a semi-structured clinical teacher interview in school children referred for diagnostic assessment of attention-deficit hyperactivity disorder (ADHD). We hypothesized that extreme scale values would increase diagnostic certainty and that classification errors would be associated with comorbid conditions.
  
  
  METHODS
  Children (n = 1038), aged 6 to 12 years, were screened using the CTRS-R and their teachers were interviewed. Three levels of T scores on the 3 Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) subscales of the CTRS-R were compared with DSM-IV symptom thresholds by interview. Where subscale scores and interviews showed highest agreement, presence of comorbid disruptive behavioural disorders, reading disability, language impairment, and low IQ were investigated for children classified correctly, compared with incorrectly.
  
  
  RESULTS
  T scores of 60 and above on all CTRS-R DSM-IV subscales offered high sensitivity, from 91% to 94%. Only on subscales M (hyperactive-impulsive) and N (total) did T scores of less than 60 offer posttest probabilities of less than 10%, confirming that a child does not reach diagnostic threshold by interview. T scores of 80 and more offered high specificity, from 88% to 93%, but did not provide high posttest probabilities that children reach diagnostic criteria. Classification errors were associated with more language impairment among false positives than true positives on the M (18.9%, compared with 11.3%, P = 0.04) and N (19.0%, compared with 9.5%, P = 0.023) subscales, and more reading disabilities among false positives than among true positives on the N subscale (35.2%, compared with 21.6%, P = 0.009).
  
  
  CONCLUSIONS
  The ability of the CTRS-R to predict whether clinically referred children reach DSM-IV criteria for ADHD at school is limited.
authors.affiliation: Research Institute, Department of Psychiatry, Hospital for Sick Children, Toronto, Ontario, Canada. alice.charach@sickkids.ca
authors.forename: Alice
authors.initials: A
authors.lastname: Charach
authors.forename: Shirley
authors.initials: S
authors.lastname: Chen
authors.forename: Sheilah
authors.initials: S
authors.lastname: Hogg-Johnson
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Schachar