Enrique Vila Abad

Polychoric versus Pearson correlations in exploratory and confirmatory factor analysis of ordinal variables

Given that the use of Likert scales is increasingly common in the field of social research it is necessary to determine which methodology is the most suitable for analysing the data obtained; although, given the categorization of these scales, the results should be treated as ordinal data it is often the case that they are analysed using techniques designed for cardinal measures. One of the most widely used techniques for studying the construct validity of data is factor analysis, whether exploratory or confirmatory, and this method uses correlation matrices (generally Pearson) to obtain factor solutions. In this context, and by means of simulation studies, we aim to illustrate the advantages of using polychoric rather than Pearson correlations, taking into account that the latter require quantitative variables measured in intervals, and that the relationship between these variables has to be monotonic. The results show that the solutions obtained using polychoric correlations provide a more accurate reproduction of the measurement model used to generate the data.

The Influence of Respiration on Biofeedback Techniques

This research is based on previous studies which identified a specific respiratory pattern and inhalation-exhalation ratio, with which we were able to obtain significantly greater reductions in psychophysiological activation than with other respiratory patterns. The present study aimed to check the effectiveness of this respiratory pattern in learning based on biofeedback from the electrical conductance of the skin. The results obtained demonstrated that biofeedback combined with this respiratory pattern produced a significant reduction in psychophysiological activation and improved learning through biofeedback techniques.

La adaptación de los test en estudios comparativos interculturales [Tests Adaptation in cross-cultural comparative studies]

Resumen La creciente globalizacion que se esta dando a nivel mundial, el problema de la emigracion y sus necesidades de adaptacion, el intercambio de estudiantes entre distintos paises fortalecido, ademas, por la creacion de un Espacio Europeo de Educacion Superior (EEES), y el creciente interes que actualmente tienen muchos paises por establecer unos estandares educativos internacionales que permitan comparar los progresos que, cada uno de ellos, han hecho en relacion con los demas, son algunos de los factores que han potenciado la preocupacion porque los instrumentos de medicion utilizados sean los adecuados y cumplan los requisitos psicometricos necesarios para su utilizacion en estudios comparativos interculturales. Las diferencias encontradas en el rendimiento obtenido por los estudiantes de los distintos paises, han de deberse a diferencias reales y no a otra serie de factores (diferencias culturales, idiomaticas, etc.) que invaliden la interpretacion de los resultados. El objetivo que nos proponemos con este trabajo es analizar brevemente las fases principales que se deben cubrir a la hora de llevar a cabo la adaptacion de un test a distintas culturas o idiomas, siguiendo las pautas marcadas por la Comision Internacional de Tests, con el fin de conseguir esos requisitos psicometricos que antes se comentaban, y hacerlo de una manera sencilla, que pueda resultar util a todas aquellas personas que, en alguna medida, esten relacionadas con el problema de la adaptacion de instrumentos para la evaluacion psicologica y/o educativa. Abstract The globalization phenomenon, the emigration and its needs of adaptation, the students mobility strengthened by the European Higher Education convergence, and the interest of the countries in stabilising international psychological and educative standards that make possible comparative studies, are some of the factors that has been promoted the interest about the instruments used in cross-cultural studies. The differences found should be based on real differences and not on other factors (culture, language, etc.) that could contaminate the interpretation of the results. Considering this problem the main objective of this paper is to analyse the phases established by the International Test Commission in test adaptation and translation. We try to show these phases in a simple way in order to provide a practical guide to the people related to psychological and educational evaluation.