10.6092/ISSN.1973-2201/3508
BRENTARI, EUGENIO; Dipartimento Metodi Quantitativi-Università Degli Studi Di Brescia
GOLIA, SILVIA; Dipartimento Metodi Quantitativi-Università Degli Studi Di Brescia
Unidimensionality in the Rasch model: how to detect and interpret
Dep. of Statistical Sciences "Paolo Fortunati", Università di Bologna
2013
PDF Document
2013
application/pdf
Statistica; Vol 67, No 3 (2007); 253-261
Unidimensionality, that is the items in a questionnaire measure only a single construct, is a fundamental requirement for the Rasch model. The paper deals with the detection of unidimensionality making use of principal components analysis of residuals and item fit statistics. Simulated bi-dimensional data sets are analized in order to find regolarities in the behavoiur of these statistical tools. The results are applied to a real database coming from the satisfaction section of the first national survey concerning the social services sector carried out in Italy
Statistica; Vol 67, No 3 (2007); 253-261