Reliability and validity of IJR Behavior Checklist scores: number versus pathology level of symptoms

The parent, teacher, and clinician forms of the IJR Behavior Checklist yield four summary scores (checklist total score, pathology-weighted total score, mean pathology score, and highest 5 items' mean pathology score). The checklist total score is essentially a symptom count with a double-weighting for frequent/intense occurrence; the other three scores incorporate item pathology weights. All four summary scores were shown to have moderately high validity as measures of the construct child/adolescent psychopathology: They differentiated between well-adjusted and clinical subsamples at the .001 level. The two scores based entirely on the pathology weights manifested less satisfactory reliability than the two scores reflecting primarily number of symptoms, but surpassed the latter in power to discriminate between psychotic and nonpsychotic patients.