Final answer:
The psychologist holds the responsibility for ensuring the validity of information provided by a test scoring and interpretation service used in client evaluations.
Step-by-step explanation:
The responsibility for the validity of information provided by a test scoring and interpretation service that a psychologist uses to make decisions about his/her clients primarily lies with the psychologist. It is essential for psychologists to ensure that the tools and services they use for assessing and making decisions about their clients are reliable and valid.
This means that psychologists must critically evaluate the reliability, validity, and appropriateness of the interpretation services before applying them to client cases. It also implies that understanding the limitations and potential biases of the tests used, such as the MMPI or projective tests, is crucial for accurate interpretations. The liability for any decisions made on the basis of such data inherently falls on the professional using the service.