A Method for Constructing a Score from Items in an Instrument with the Concept of Agreement

• Activity Number: 356
• Type: Contributed
• Date/Time: Tuesday, August 11, 2015 : 10:30 AM to 12:20 PM
• Sponsor: Mental Health Statistics Section
• Author(s): Lijia Wang* and Limin Peng and Ying Guo and Amita K. Manatunga
• Companies: Emory University and Emory University and Emory University and Emory University
• Keywords: broad sense agreement ; optimal weights ; PTSD diagnosis

Abstract

In many medical studies, questionnaires or instruments consisting many items are used to measure the health outcomes reflecting a disease status. In such studies, how to combine the items to derive a total score that reflects the disease status is a challenging task. We propose a new method to derive a weighted score that can assign different weights to different items while providing the highest agreement between the new score and the disease status. Specifically we propose to find optimal weights by maximizing the broad sense agreement (Peng et al., 2011) between the new instrument and the ordinal gold standard. Theoretical and simulation results demonstrate the validity of our proposed optimal weights. We apply our method to a PTSD study to investigate the performance of the new instrument.