Lack of prognostic, or predictive validity with respect to the outcome of treatment, or later behavior. Individual differences between groups of normal subjects. Failure to find any significant relationships between Rorschach scores and intelligence, or creative ability. In 1953, Fiske and Baughman reported that practitioners feel that the variation in the total number of responses is too much to be able to interpret the ratio scores adequately. Also, the meaning of the indices changes depending upon the length of the protocol, because the relationship between Rorschach scores and the total number of responses is complex and curvilinear.
Many workers compute percentage ratio in an effort to control the length of the protocol.
The analysis of responses to inkblots has ranged all the way from one extreme to the other of the projective psychometric continuum. Wayne Holtzman developed an inkblot test to overcome some of the limitations of the Rorschach. As Fiske and Baughman pointed out, the relationship between Rorschach scores and the total number responses are complex and curvilinear. Consequently, the usual effect of R linear regression methods for removing the confounding effect of R will generally fail. When the groups of Normal, Neurotics, and Schizophrenics were divided, on the basis of number of responses, into high productivity and low productivity, many indices which were found to be significant lost their significance.