The visualisation of Rasch model analysis

Rasch analysis is a member of the Item Response Theory (IRT) family and is increasingly used to assess construct validity in psychometrics. The analysis is normally used to predict a person’s ‘behaviour’ when responding to items, for example, in an emotional intelligence questionnaire and, in greater use, this model allows generalisation to other people taking the same test (Molenaar, 1995). This paper presents a visualisation of a Rasch analysis on a dataset of 938 students completing the Trait Emotional Intelligence-Short Form (TEIQ-SF) questionnaire. TEIQ-SF is an instrument to measure the emotional intelligence. The first part of this paper describes the fundamental principles of Rasch analysis and then details the psychometric claims of TEIQ-SF. It then describes the algorithm underpinning the calculations in Rasch analysis. Finally this algorithm is applied to the data from responses to TEIQ-SF. By using advance web techniques, the process of Rasch analysis can be visualised for the purpose of enhancing communication of a difficult to understand but very useful psychometric technique.