The Brief Symptom Inventory (BSI) - Service correctionnel du Canada

The BSI manual provides norms based on four groups each separated for males and
females: adult non-patients, adult psychiatric outpatients, adult psychiatric inpatients and
adolescent non-patients. The test author advises that the Global Severity Index is the scale
that is the most sensitive single indicator of distress. The author has not set cut-off scores to
determine when further evaluation is warranted. He does advise, however, that using the
reference group of adult non-patients a T-score of 63 or above on the GSI or a T-score of 63
and above on any two dimensions would be considered a “case” worthy of further evaluation.
This report examined the percentage of offenders who fell at or above a T-score of 65 since
the mental health division of CSC chose this cut-off to flag a case for follow up. Some
psychologists, however, may opt for a more liberal criterion to reduce the chance of over
looking offenders who may require additional services. The results, therefore, also present
the percentage of offenders who would meet a T60 criterion.
An individual with a given raw score will receive different T-scores depending upon
the population on which the scores are normed. For example, a raw score of 0.68 on the
Global Severity Index could place the offender at the 93 rd percentile using non patient norms
which is a high score, but at the 46 th percentile compared to an in-patient population, a
moderate score. Deciding which population is a suitable comparison is not always straight-
forward. Although there is evidence of substantial mental disorder among offenders, they are
not a psychiatric population so for this project the adult non patient group was chosen as the
reference population. Estimates using the T-65 cut-off for the outpatient and in-patient
psychiatric norms are also provided in order to compare the degree of distress of federal
offenders to that of psychiatric populations. Given the large number of federal offenders who
completed this assessment and the uniqueness of the population it was feasible to develop
norms relevant to this population. To develop the CSC norms for male offenders on the
scales and the GSI of the BSI, a large sample was selected to represent the population of
male CSC offenders and estimate the population mean and variability of the scale and GSI
scores. For example, the mean raw score on the GSI of 0.69 was rescaled to a normative
distribution of 50. The standard deviation of the distribution of raw scores was rescaled to be
10. The raw score that corresponds to a given T-score is calculated through the following
formula: Raw Score = raw mean + [(given T-score - 50) (raw score standard deviation)]/10.
Further research is required to identify meaningful cut-off scores using the CSC norms.
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