ABSTRACT
Simple structure is the widely used principle for rotation, but the selection of this principle is mathematically arbitrary. The criteria of simple structure were used by Louis Leon Thurstone to provide a psychologically meaningful solution to the problem of the indeterminacy of the factors. Thurstone hoped that the factor pattern of any given variable would be constant when the variable was included in factor analysis containing the same common factors. The interpretation of a factor is based upon the variables that are and are not related to that factor. When the factors are uncorrelated, one matrix summarizes factor-variable relationships. The basic matrix for interpreting the factors is the factor structure. The purpose of a cluster analysis of variables is to group together those variables that are most alike and it can aid in the interpretation of factors by bringing together variables of a similar composition.
