The Behavior Problems Inventory-Short Form for individuals with intellectual disabilities: part II: reliability and validity.

BACKGROUND: The Behavior Problems Inventory-01 (BPI-01) is an informant-based behaviour rating instrument for intellectual disabilities (ID) with 49 items and three sub-scales: Self-injurious Behavior, Stereotyped Behavior and Aggressive/Destructive Behavior. The Behavior Problems Inventory-Short Form (BPI-S) is a BPI-01 spin-off with 30 items. METHODS: The psychometric properties of these two versions of the scale were computed using aggregated archival data from nine different sites in the USA, Wales, England, the Netherlands and Romania with a total of 1122 cases with a BPI-01 total score >0. RESULTS: The internal consistency of the BPI-01 and the BPI-S ranged from fair to excellent with the BPI-01 showing slightly stronger reliability. Construct validity (confirmatory and discriminant) was computed by comparing BPI sub-scale scores with the scores of four other behaviour rating scales (the Aberrant Behavior Checklist, the Diagnostic Assessment for the Severely Handicapped-II, the Nisonger Child Behavior Rating Form and the Inventory for Client and Agency Planning). Strong evidence for confirmatory and discriminant validity was found for both the BPI-01 and the BPI-S. Confirmatory fit indices for the BPI and the BPI-S were comparable and suggesting that the factor structures fit the data well. CONCLUSION: In summary, both BPI versions were found to be equally sound psychometrically and can be endorsed for future use. However, independent future studies are needed to replicate the psychometrics of the BPI-S with new data.

The Behavior Problems Inventory-Short Form for individuals with intellectual disabilities: part I: development and provisional clinical reference data.

BACKGROUND: The Behavior Problems Inventory-01 (BPI-01) is an informant-based behaviour rating instrument that was designed to assess maladaptive behaviours in individuals with intellectual disabilities (ID). Its items fall into one of three sub-scales: Self-injurious Behavior (14 items), Stereotyped Behavior (24 items), and Aggressive/Destructive Behavior (11 items). Each item is rated on a frequency scale (0 = never to 4 = hourly), and a severity scale (0 = no problem to 3 = severe problem). The BPI-01 has been successfully used in several studies and has shown acceptable to very good psychometric properties. One concern raised by some investigators was the large number of items on the BPI-01, which has reduced its user friendliness for certain applications. Furthermore, researchers and clinicians were often uncertain how to interpret their BPI-01 data without norms or a frame of reference. METHODS: The Behavior Problems Inventory-Short Form (BPI-S) was empirically developed, based on an aggregated archival data set of BPI-01 data from individuals with ID from nine locations in the USA, Wales, England, the Netherlands, and Romania (n = 1122). The BPI-S uses the same rating system and the same three sub-scales as the BPI-01, but has fewer items: Self-injurious Behavior (8 items), Stereotyped Behavior (12 items), and Aggressive/Destructive Behavior (10 items). Rating anchors for the severity scales of the Self-injurious Behavior and the Aggressive/Destructive Behavior sub-scales were added in an effort to enhance the objectivity of the ratings. RESULTS: The sensitivity of the BPI-S compared with the BPI-01 was high (0.92 to 0.99), and so were the correlations between the analogous BPI-01 and the BPI-S sub-scales (0.96 to 0.99). Means and standard deviations were generated for both BPI versions in a Sex-by-age matrix, and in a Sex-by-ID Level matrix. Combined sex ranges are also provided by age and level of ID. CONCLUSION: In summary, the BPI-S is a very useful alternative to the BPI-01, especially for research and evaluation purposes involving groups of individuals.