Doing More with Less: Improving Scale Performance Using Classical and Modern Theory Techniques

• Activity Number: 8
• Type: Invited
• Date/Time: Sunday, July 31, 2011 : 2:00 PM to 3:50 PM
• Sponsor: Section on Statistical Consulting
• Author(s): Richard F. Ittenbach*+
• Companies: Cincinnati Children's Hospital Medical Center
• Keywords: scale development ; psychometrics ; Rasch Models ; True Score Theory ; validity

Abstract

Statisticians are increasingly being asked to consult on the development and validation of new measures appropriate for use in health-care settings. Whether one is interested in specific, diagnostic measures or more traditional paper and pencil screening instruments, the challenges of scale development are as much technical as they are procedural. Historically, Classical True Score Theory has served as the basis for scale development approaches. More recently, new approaches like Rasch Modeling and Item-Response Theory, generally referred to as Modern Theory techniques, have begun to replace Classical True Score Theory as the method of choice. Indices of item functioning, factor simplicity, and item-fit statistics are now considered to be as important to the scale development and validation process as the more traditional content-, criterion-, and construct-related techniques of prior eras. Rather than simply discard one theoretical framework for another, the purpose of this presentation will be to make a case for incorporating elements of both theoretical approaches when one seeks to develop, validate, or refine a new measure.