Factor analysis may be R-type factor analysis or it may be Q-type factor analysis. In R-type factor analysis, high correlations occur when respondents who score high on variable 1 also score high on variable 2 and respondents who score low on variable 1 also score low on variable 2. Factors emerge when there are high correlations within groups of variables. In Q-type factor analysis, the correlations are computed between pairs of respondents instead of pairs of variables.
High correlations occur when respondent 1‘s pattern of responses on all the variables is much like respondent 2‘s pattern of responses. Factors emerge when there are high correlations within groups of people. Q-type analysis is useful when the object is to sort out
people into groups based on their simultaneous responses to all the variables. Factor analysis has been mainly used in developing psychological tests (such as IQ tests, personality tests, and the like) in the realm of psychology. In marketing, this technique has been
used to look at media readership profiles of people.
