OBJECTIVE:To develop outpatient Adaptive Short Forms for the Activity Measure for Post-Acute Care item bank for use in outpatient therapy settings. DESIGN:A convenience sample of 11,809 adults with spine, lower limb, upper limb, and miscellaneous orthopedic impairments who received outpatient rehabilitation in 1 of 127 outpatient rehabilitation clinics in the United States. We identified optimal items for use in developing outpatient Adaptive Short Forms based on the Basic Mobility and Daily Activities domains of the Activity Measure for Post-Acute Care item bank. Patient scores were derived from the Activity Measure for Post-Acute Care computerized adaptive testing program. Items were selected for inclusion on the Adaptive Short Forms based on functional content, range of item coverage, measurement precision, item exposure rate, and data collection burden. RESULTS:Two outpatient Adaptive Short Forms were developed: (1) an 18-item Basic Mobility Adaptive Short Form and (2) a 15-item Daily Activities Adaptive Short Form, derived from the same item bank used to develop the Activity Measure for Post-Acute Care computerized adaptive testing program. Both Adaptive Short Forms achieved acceptable psychometric properties. CONCLUSIONS:In outpatient postacute care settings where computerized adaptive testing outcome applications are currently not feasible, item response theory-derived Adaptive Short Forms provide the efficient capability to monitor patients' functional outcomes. The development of Adaptive Short Form functional outcome instruments linked by a common, calibrated item bank has the potential to create a bridge to outcome monitoring across postacute care settings and can facilitate the eventual transformation from Adaptive Short Forms to computerized adaptive testing applications easier and more acceptable to the rehabilitation community.