(1) The authors concur with Tukey in treating the standardized and concrete forms of correlational statistics as if they were alternative conceptions between which it is necessary to make a choice. It has always seemed to me that these should be looked upon as two aspects of a single theory corresponding to different modes of interpretation which, taken together, often give a deeper understanding of a situation than either can give by itself. (2) E1ven when the sole objectives of analysis are the concrete coefficients, actual path analysis takes a simpler and more homogeneous form in terms of the standardized ones. The application of the method to data usually requires algebraic manipulation of coefficients pertaining to unmeasured variables on the same basis as measured ones. As the former can only be dealt with in standardized form, homogeneity requires that all be so dealt with in the course of the algebra. It is such a simple matter to pass from either form to the other (in the cases in which standard deviations are available to all) that the economy of effort in using the concrete coefficients as far as possible, where these are the objectives, is usually outweighed by the loss of economy in other respects. (3) It is of first importance in path analysis to make use of all of the available data. This is not done by Turner and Stevens in most of their examples. The use of standardized coefficients leads naturally

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