This study examines the psychometric properties of the Vanderbilt AD / HD Diagnostic Teacher Rating Scale (VADTRS) and provides preliminary normative data from a large, geographically defined population. (link.springer.com)
The collection and description of normative data within specific populations is important as differing means are possible both as a consequence of actual differences in the prevalence of particular difficulties between different populations and as a result of cultural biases and expectations as to what is «normal» on the part of raters with differing backgrounds and experiences. (capmh.biomedcentral.com)
For those interested, the survey tools used in California will soon be released with normative data from 500,000 students. (bluum.org)