An Algorithm for Testing Unidimensionality and Clustering items in Rasch Measurement
by Rudolf Debelak & martin Atrendasy (2012).
A new algorithm was proposed to fit the unidimensional Rasch model in a multidimensional item set. The proposed method is intended to be used prior to the application of other model tests that have power against specific model violations. Thus, this method could also serve an alternative to other approaches for the assessment of unidimensionality in the context of Rasch measurement. By the simulation studies, the results show a good fit to the Rasch model but with some limitations, such as the good fit is under the larger sample size of person and the correlation of 0.0 between the person parameters.
Questions:
1. With regard to the “The Basic Structure of the Procedure” section, it is not very clear for me to understand what the definition of item set is and how to use this procedure.
2. The explanations for the two tables are too short.