The stereotyped behavior scale: psychometric properties and norms.

The Stereotyped Behavior Scale (SBS) is an empirically developed behavior rating scale for adolescents and adults with mental retardation (Rojahn, Tassé & Sturmey, 1997). Since the original publication, one item was deleted and two items were merged, leaving 24 items. In an additional change, severity scales were added to the frequency scales. In this paper, psychometric properties and (relative) norms for the new SBS are presented. In the psychometric study, 45 adults with mental retardation from a residential facility participated. Of these, 15 were selected for high-rates or very severe forms of stereotyped behaviors, 15 for mild to moderate rates or less severe stereotypies, and 15 for the low rates or absence of stereotyped behaviors. Direct care staff familiar with the participants completed the SBS and the "Stereotypy" subscale of the Aberrant Behavior Checklist-Residential (ABC-R) (Aman, Singh, Stewart & Field, 1985). For 15 participants, two raters independently completed the SBS. In addition, 45-min direct behavior observations were conducted on 16 participants. After approximately four weeks, the instruments were completed a second time by the same raters. As for reliability, the SBS frequency and severity scale total scores yielded test-retest intraclass coefficients (ICC) of 0.93 and 0.71, ICC interrater agreement of 0.76 and 0.75, and each had an internal consistency a of 0.91. For criterion validity, the SBS frequency and severity scores correlated with the ABC-R "Stereotypy" score at 0.80 and 0.84 (Pearson r), with systematic behavior observations at 0.50 and 0.65 (Pearson r), and with the a priori classification at 0.50 and 0.65 (Spearman p). From a previous data set of 550 individuals with stereotypic behavior, normative data (percentile ranks and T-scores) were derived. The data were presented in two tables, one showing a breakdown of gender by age groups, and the second one of age groups by level of functioning.