Sentence:  Hence, the idea of nonlinear <WSD>factor analysis</WSD> should not be treated as an extension of the basic <WSD>factor analysis</WSD> concept, but should be considered as an inherent effort to make <WSD>factor analysis</WSD> more complete and useful. 
Meaning of the word marked with <WSD> tags:  A statistical method used to describe variability among observed correlated variables in terms of one or more unobserved variables (called factors).