Published online by Cambridge University Press: 01 January 2025
Factor analysis and principal component analysis result in computing a new coordinate system, which is usually rotated to obtain a better interpretation of the results. In the present paper, the idea of rotation to simple structure is extended to two dimensions. While the classical definition of simple structure is aimed at rotating (one-dimensional) factors, the extension to a simple structure for two dimensions is based on the rotation of planes. The resulting planes (principal planes) reveal a better view of the data than planes spanned by factors from classical rotation and hence allow a more reliable interpretation. The usefulness of the method as well as the effectiveness of a proposed algorithm are demonstrated by simulation experiments and an example.
The author is most grateful to the referees, the Associate Editor, and the Editor for helpful suggestions, which resulted in a completely improved version of an earlier manuscript. The author also wants to express his gratitude to Johann Millendorfer, the former head of STUDIA, who initiated the idea of this work.