Measuring individuals' response quality in self-administered psychological tests: an introduction to Gendre's functional method.

The functional method is a new test theory using a new scoring method that assumes complexity in test structure, and thus takes into account every correlation between factors and items. The main specificity of the functional method is to model test scores by multiple regression instead of estimating them by using simplistic sums of points. In order to proceed, the functional method requires the creation of hyperspherical measurement space, in which item responses are expressed by their correlation with orthogonal factors. This method has three main qualities. First, measures are expressed in the absolute metric of correlations; therefore, items, scales and persons are expressed in the same measurement space using the same single metric. Second, factors are systematically orthogonal and without errors, which is optimal in order to predict other outcomes. Such predictions can be performed to estimate how one would answer to other tests, or even to model one's response strategy if it was perfectly coherent. Third, the functional method provides measures of individuals' response validity (i.e., control indices). Herein, we propose a standard procedure in order to identify whether test results are interpretable and to exclude invalid results caused by various response biases based on control indices.

Identity in schizophrenia: a study of trait self-knowledge.

Identity results from interlock of two systems which are a set of abstracted representations about oneself and a phenomenological self. Literature highlights identity disturbance in schizophrenia that affects each of both systems. In the same vein, the present study investigates the stability and the quality of traits self-knowledge, a component of abstracted representations of self, in schizophrenia patients. Sixty-eight patients with schizophrenia and 68 healthy control subjects completed a short version of a personality scale (LABEL). This scale is composed of two versions (A and B), each comprising 50 adjectives that correspond to synonymous adjectives in the alternate list. Participants indicated how these adjectives described themselves and completed both versions of the scale on two separate occasions, one month apart. The findings showed that schizophrenic patients presented an unstable identity and change in identity quality compared with healthy subjects. However, this identity disturbance was weaker than expected. These results are discussed in a part of autobiographical memory disturbances in schizophrenia, illness duration and the decompensation stage.