Probabilistic Unfolding Theory And Research Method In Personality Assessment

In psychological measurement, the cumulative response and the cumulative response are two types of basic response mechanisms from a set of single-stimulus. In the cumulative response mechanism, higher levels of the latent trait should, in all probability, lead to higher item scores, which, in turn, should lead to higher total test scores. Commonly the cumulative response mechanism is used in achievement testing. In the unfolding response mechanism, higher item scores should, in all probability, be observed to the extent that the individual and the item are located close to each other on the latent continuum. The unfolding response mechanism suggests that the person' s idea-point governs the response in this way: the closer the person-item distance, the higher the expected score of the person on the item. Unfolding models are, thus, proximity models that predict item scores, and consequently total scores, on the basis of the distances between a given individual and each item in question. The unfolding response models have been useful in studies of personality and attitude. Some researches overseas indicate that the unfolding models fit the data of 16PF better than the cumulative models.However, in the studies of the personality assessment in China, almost researchers use the Classical Test Theory(CTT) or the cumulative model to assess the personality and there is few researches about unfolding theory. The current research will summarize the unfolding models and the personality assessment about 16PF, and particularly, by the general unfolding model, the Hyperbolic Cosine Model(HCM) ( Andrich & Luo, 1993;Luo,1998;Luo, 2001), analyze the 16PF scale in China.The main purposes of the study are to validate further that the unfolding models fit the personality measurement better than other models and to assess the quality of the 16PF scale.The dissertation involves four aspects.In the first aspect, the research actuality of unfolding models willbe introduced, including dichotomous and polytomous responses. This part mostly focuses on introducing the unfolding models and clarifying the idea that the HCM is the general form of unfolding models. This part also illustrates the cumulative models fit the achievement test and unfolding models fit the personality or attitude test.In the second aspect, taking the example of the 16PF scale, the research analyzes the overseas and domestic test about the personality. And it has come to conclusion that the unfolding models are more appropriate for non-cognitive measurement than the cumulative ones.In the third part, by HCM, a practical analysis is processed on the 16PF, which including the analyses on the item, person, and scale structure. At the same time, the data are compared with the results by CTT.In the fourth part, the related theories and the practical research are discussed comprehensively.The present research demonstrates that:First, the two measurement types are different from the response patterns and the mathematical models. In all the unfolding models, the HCM is the general form.Secondly, in the personality assessment, the response pattern of the person is the unfolding model dominated by idea-point, but not the cumulative model.Third, the unfolding models are more appropriate to 16PF scale than the cumulative ones.Finally, the research proposes that there are some deficiencies in the current version of 16PF scale using in China. It is necessary to update and revise the scale in the near future.