Reconsidering Focus Groups and Rasch Model Item Response Theory in Instrument Development

Abstract

In this rejoinder, we focus on five important themes derived from the valuable comments of Harvey; Wang, Hogge, and Sahai; and Whittaker and Worthington. Specifically, we reflect on (a) methodological and conceptual issues associated with the use of focus groups in developing an initial item pool, (b) the debate about the use of Rasch versus other item response theory (IRT) models, (c) response scale functioning and the use of item parcels, (d) bandwidth and scale sensitivity, and (e) multicultural considerations. We reconsider the strengths and limitations of the approaches that we have endorsed in light of the comments of our colleagues. We conclude with the hope that dialogue on the use of focus groups and IRT in measurement development and on multicultural assessment continues.