The comparison of the Behavioral Observation System and the Brief Psychiatric Rating Scale-Expanded

The construct validity of the Behavioral Observation System (BOS), an observational instrument used by line staff to rate psychopathological behaviors, was studied using comparisons with the Brief Psychiatric Rating Scale—Expanded version (BPRS‐E). A sample of 100 inpatient participants was rated using the BPRS‐E on the same day they were rated by line staff using the BOS. Pearson product–moment correlations were performed, supporting good convergence and divergence. Principle component analysis on the six BPRS‐E scales and the four BOS scales resulted in a three‐factor finding. This analysis was supportive of construct validity. Uses of the BOS in light of these findings were discussed. © 2002 Wiley Periodicals, Inc. J Clin Psychol 58: 847‐852, 2002.