Unidimensional Interpretations for Multidimensional Test Items

Kahraman N.

JOURNAL OF EDUCATIONAL MEASUREMENT, cilt.50, sa.2, ss.227-246, 2013 (SSCI) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 50 Sayı: 2
  • Basım Tarihi: 2013
  • Doi Numarası: 10.1111/jedm.12012
  • Dergi Adı: JOURNAL OF EDUCATIONAL MEASUREMENT
  • Derginin Tarandığı İndeksler: Social Sciences Citation Index (SSCI), Scopus
  • Sayfa Sayıları: ss.227-246
  • Gazi Üniversitesi Adresli: Hayır

Özet

This article considers potential problems that can arise in estimating a unidimensional item response theory (IRT) model when some test items are multidimensional (i.e., show a complex factorial structure). More specifically, this study examines (1) the consequences of model misfit on IRT item parameter estimates due to unintended minor item-level multidimensionality, and (2) whether a Projection IRT model can provide a useful remedy. A real-data example is used to illustrate the problem and also is used as a base model for a simulation study. The results suggest that ignoring item-level multidimensionality might lead to inflated item discrimination parameter estimates when the proportion of multidimensional test items to unidimensional test items is as low as 1:5. The Projection IRT model appears to be a useful tool for updating unidimensional item parameter estimates of multidimensional test items for a purified unidimensional interpretation.