An Independent Investigation Into the Psychometric Properties of the Adult Scale of Hostility and Aggression (A-SHARP)

ABSTRACT

Background: The Adult Scale of Hostility and Aggression (A-SHARP) rating scale assesses the frequency/severity (problem scale) and the reactive-proactive motivation (provocation scale) of aggressive behaviors in adults with intellectual disabilities (ID). Items are assigned to five subscales (Verbal Aggression, Physical Aggression, Hostile Affect, Covert Aggression, and Bullying). Although psychometric properties reported by the scale’s developers were very good, we wanted to corroborate them independently. We were also interested in whether the reactive-proactive distinction of aggressive behavior is related to a behavioral/functional classification. Method: Staff at a day-treatment program for adults with ID completed ratings for 155 clients using the A-SHARP, the Behavior Problems Inventory-01 (BPI-01), and the Questions about Behavioral Function (QABF). Results: Internal consistency was found to be excellent, and the A-SHARP Physical Aggression subscale had good congruent and clinical validity. Confirmatory factor analysis showed sufficient evidence toward the factorial validity of the A-SHARP’s problem scale. The reactive-proactive classification of aggressive behavior motivation by the A-SHARP’s provocation scale was independent of the functional classification. Conclusions: The A-SHARP is a useful addition to a small number of existing instruments for assessing aggressive behavior in adults with ID, especially its problem scale. We discuss how the A-SHARP provocation scales might provide therapy-relevant information. Empirical evidence for the clinical utility of the A-SHARP provocation scale will have to be established by future research.

KEYWORDS:

• Aggression
• assessment
• developmental disabilities
• intellectual disabilities
• A-SHARP
• BPI-01

Acknowledgments

This article is based on the research conducted by the second author in partial fulfillment of the requirements for her master of arts degree.

The authors express their appreciation to Christopher Pritchard, Bridget Pritchard, and Joseph Fuemmeler, Chrestomathy, Inc. program directors who were responsible for the coordination of rater training and data collection, and to all staff members who contributed to this project. We are also especially indebted to Josh Moore for diligent data management.

Notes

¹ A companion to the A-SHARP, the Children’s Scale for Aggression and Hostility; Reactive/Proactive (C-SHARP) is also available (Farmer & Aman, 2009).

² > .80 = nearly perfect, between > .75 and .80 = excellent, between > .60 and .74 = good, between > .40 and .59 = fair, and < .40 = poor.