Abstract
A new criterion which is based on the principle of linear regression analysis is proposed concerning the estimation of the number of factors in multiple factor analysis. Following a short historical review on the number of factors, the emphasis is placed on the necessity of a new type of criterion, and a linear regression criterion is proposed based on the regression of the reproduced off-diagonal elements with an assigned number of factors on the corresponding elements in the original correlation matrix. In the last section some related important topics which are necessary for further sophistication of our proposal are discussed.