Biomedical subjects

Urbano Lorenzo-Seva

Publications and source records attributed to Urbano Lorenzo-Seva.

4 recordsLinked to original sources

PubMed2006

FACTOR: a computer program to fit the exploratory factor analysis model.

Exploratory factor analysis (EFA) is one of the most widely used statistical procedures in psychological research. It is a classic technique, but statistical research into EFA is still quite active, and various new developments and methods have been presented in recent years. The authors of the most popular statistical packages, however, do not seem very interested in incorporating these new advances. We present the program FACTOR, which was designed as a general, user-friendly program for computing EFA. It implements traditional procedures and indices and incorporates the benefits of some more recent developments. Two of the traditional procedures implemented are polychoric correlations and parallel analysis, the latter of which is considered to be one of the best methods for determining the number of factors or components to be retained. Good examples of the most recent developments implemented in our program are (1) minimum rank factor analysis, which is the only factor method that allows one to compute the proportion of variance explained by each factor, and (2) the simplimax rotation method, which has proved to be the most powerful rotation method available. Of these methods, only polychoric correlations are available in some commercial programs. A copy of the software, a demo, and a short manual can be obtained free of charge from the first author.

Behavioral Research↗

PubMed2005

IRT-related factor analytic procedures for testing the equivalence of paper-and-pencil and Internet-administered questionnaires.

This article describes a general item response theory-based factor analytic procedure that allows assessment of the equivalence between 2 administrative modes of a questionnaire: paper and pencil, and Internet based. The theoretical relations between the present procedure and other methods used in previous empirical research are shown, and the advantages of the procedure are discussed. An empirical application based on 2 personality questionnaires is given, and the results are compared with the results of using traditional procedures for assessing equivalence. The substantive implications of the results, as well as suggestions for further research and methodology, are discussed.

Factor Analysis, Statistical↗

PubMed2003

Imince: an unrestricted factor-analysis-based program for assessing measurement invariance.

In this article, a Windows program for analyzing measurement invariance in two different populations is described. Factor analysis is a common way of assessing measurement invariance, and restricted factor analysis is now the most popular method. However, applied researchers have usually found that the theoretical advantages of restricted factor analysis do not always apply in practical situations. For example, when the participant sample is large, as is the case in Internet-based questionnaires, the available software for restricted factor analysis might fail to converge on a solution. Our program is based on unrestricted factor analysis and considers the three parameters that define factor invariance: difficulties, discriminations, and residual variances. The statistical significance of the tests for evaluating invariance is obtained using Bootstrap resampling procedures. A real-life example demonstrates the usefulness of the program.

Adult↗

PubMed2002

Techniques for oblique factor rotation of two or more loading matrices to a mixture of simple structure and optimal agreement.

Three techniques are proposed for oblique rotation of two or more loading matrices to a mixture of simple structure and optimal agreement. The three techniques, consensus direct oblimin, consensus promin and consensus simple target rotation, are compared to existing techniques and to each other, using artificial and real data. When agreement between solutions can be expected, the new techniques appear to be more useful than oblique rotation of each of the loading matrices separately. Consensus direct oblimin achieved the best results in terms of 'agreement between simple structures'; consensus promin was the technique that best recovered the underlying simple loading matrix; and consensus simple target rotation seemed to give an interesting compromise between agreement and simple structure, focusing a little more on simplicity than consensus direct oblimin.

Algorithms↗