The most salient criticism regarding the MMPI test is a) the restructuring of the new test (the MMPI-2) and b) the dramatic differences in the results obtained between Caucasians and members of another race, namely African Americans.
The criticism about the restructuring of the original MMPI is based on the claim that the old and new tests are quite similar, creating a problem in the codification of the answers. That particular criticism is planned to be solved by creating a new codification system altogether. This argument would be valid because patients who are tested with the original MMPI must have codes that are transferable to the code-results of the MMPI-2 or else the test would have to be taken all over. However, continuity between one test and the next must be there.
The second criticism is the differences in the scores between Caucasians and minorities. In this case, the reason for this to occur may be that the test has not open viable answers as perceived from a different culture. After all, the test was originally intended to test mostly Caucasian males. This is a valid argument as well, however, the MMPI-2 is not meant to be the only assessment tool to be used to assess a patient. The Rorschach technique, clinical interviews, empirical data and other cognitive analyses are equally important and should be used in conjunction with the MMPI-2. Assessments are made by humans and they are prone to miscues as with everything else. Hence, we cannot blame one test alone for what could be explained by the implementation of additional research sources and tools.