Abstract

VITORIA, Florbela; ALMEIDA, Leandro S.  and  PRIMI, Ricardo. Psychological test´s unidimensionality: concept, procedures and difficulties in their assessment. Psic [online]. 2006, vol.7, n.1, pp. 01-07. ISSN 1676-7314.

The most usual models of Item Response Theory (IRT) presuppose that the collection of items composing the test only measures one single factor or construct, meaning that the test is unidimensional. Two kinds of questions and difficulties arise at this point: (1) diverse factors, for instance, cognitive and personality characteristics of respondents may interfere with answers to the test, beyond the study variable, which affects unidimensionality; (2) there are no consensuses on empirical criteria for unidimensionality determination, so it is assumed in terms of degree of dimensionality. We intended, on this paper, to make a brief review of the main definitions for the concept and evaluation methods of unidimensionality.

Keywords : Unidimensionality; Psycological tests; Psychometric; Factor analisys.

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