Rasch analysis for psychometric improvement of science attitude rating scales

ABSTRACT

Students’ attitude towards science (SAS) is often a subject of investigation in science education research. Survey of rating scale is commonly used in the study of SAS. The present study illustrates how Rasch analysis can be used to provide psychometric information of SAS rating scales. The analyses were conducted on a 20-item SAS scale used in an existing dataset of The Trends in International Mathematics and Science Study (TIMSS) (2011). Data of all the eight-grade participants from Hong Kong and Singapore (N?=?9942) were retrieved for analyses. Additional insights from Rasch analysis that are not commonly available from conventional test and item analyses were discussed, such as invariance measurement of SAS, unidimensionality of SAS construct, optimum utilization of SAS rating categories, and item difficulty hierarchy in the SAS scale. Recommendations on how TIMSS items on the measurement of SAS can be better designed were discussed. The study also highlights the importance of using Rasch estimates for statistical parametric tests (e.g. ANOVA, t-test) that are common in science education research for group comparisons.