Variability in staff reports of the frequency of challenging behavior.

Information was collected from 88 staff about their observations of the occurrence and frequency of challenging behaviors in 22 individuals with developmental disabilities with whom they worked. Staff reports suggested considerable variability in challenging behavior in the presence of different staff and, from day to day, in the presence of the same staff. Variability was greater for stereotyped than for aggressive/destructive behavior, and for more frequent behavior. Managers reported generally less challenging behavior than their staff. The validity of the findings was discussed and their implications for research and practice considered.