Under what circumstance may psychologists refrain from providing test data?

The correct option emphasizes the ethical responsibility psychologists have when it comes to providing test data to their clients. Psychologists may refrain from sharing test data primarily to protect against substantial harm or misuse of the data. This reflects a key principle in psychological practice, where the welfare of the client is of utmost importance. The responsibility to prevent harm entails being cautious about how test results could be interpreted or used by the client or others, potentially leading to misunderstanding or misuse of sensitive information.

In some situations, sharing test data might lead to anxiety or misinterpretation, particularly if the client lacks sufficient background knowledge to understand the implications of the results. Thus, when there is a clear risk of causing substantial harm or misuse, it is ethically justifiable for psychologists to withhold that information.

The other options focus on circumstances that, while relevant, do not meet the stringent criteria required to justify withholding test data. For instance, test data being too complex, the client's lack of request, or the irrelevance of the tests to treatment do not inherently pose the same level of risk to the client’s well-being or misinterpretation of the data. Therefore, the emphasis on protecting individuals from potential harm is central to professional ethical guidelines in psychology.