We used an item response theory (IRT) measurement model to examine the
28-item Conners Teacher's Rating Scale (CTRS) for the diagnosis of at
tention-deficit/hyperactivity disorder (ADHD). Using an Israeli sample
of 453 pairs of respondents (parents and teachers), we broke down our
sample into nonclinical (n = 306) and clinical (n = 147) subsamples.
IRT analyses based on a rating scale model revealed structural inadequ
acies involving the apparent inappropriateness of the 4-point Likert-t
ype scale used by the CTRS. Additionally, IRT analyses were able to sh
ed light on differences in the structure of the latent trait for the A
DHD variable as measured by the CTRS for all four groups of respondent
s. Implications for the diagnosis and treatment of ADHD are presented.