Due to the relative inability of individuals with intellectual disabilities (ID) to provide an accurate and reliable self-report, assessment in this population is more difficult than with individuals in the general population. As such, assessment procedures must be adjusted to compensate for the relative lack of information that the individual can provide and rely more on the behavioral expression of communication. One method commonly used is the indirect functional assessment that utilizes behavior rating scales that have been developed to gather behavioral data in a short time. One of the few empirically derived and psychometrically sound is the QABF, a 25-item questionnaire designed to rate specific behavioral functions and maintaining variables. The purpose of this study was to conduct an item analysis to determine the psychometric properties of the QABF and determine if a short form version could be developed that is both psychometrically valid and reliable, and clinically useful. Results of the item selection procedure indicted that the original 25 items could be reduced by ten. Test tryout procedures showed that the QABF-SF maintained the original five factor structure of the original while maintaining the high degree of reliability and validity. The QABF-SF appears to be a useful tool to aid clinicians in the brief functional assessment of behavior in individuals with ID. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com.bibliotheek.ehb.be/en-US/products/dissertations/individuals.shtml.]