Skeptic,

You said:

Quote:

There is debate, even now, over the efficacy of "security through obscurity".  Encryption algorithms are a prime example:  although a case can be made that keeping algorithms secret provides an additional layer of protection, no cryptographer worth his or her salt would ever base the security of an algorithm on this principle.  In fact, good cryptographic design is completely dependent upon the algorithm being secure even if all details about it are public knowledge.  The same should be the case for physical security of a premesis -- which is where your analogy falls apart.

I certainly agree with you when it comes to encryption.  However, psychological tests are a different matter.  Most psychological tests, be they personality tests such as the MMPI-2 or forensic tests, were developed on populations of naive test takers.  Once the tests have been developed, attempts are made to safeguard against those trying to fake good or otherwise manipulate or invalidate them.  The MMPI-2, for example, contains a Lie scale and a Frequency scale, among others, to alert the examiner to such attempts.  

But if someone were to purchase the test booklets, scoring protocols, and analysis books; if they knew which questions belong to which scales and how they are answered in the normal or deviant manner; if they were to plan what type of profile they wish to project and studied sufficiently well, then the psychologist's task at determining their true psychological profile would be more difficult.  This is why the psychological community tries to prevent the dissemination of that type of information to the potential test takers.

Is the information classified?  No; certainly not by the Government.  But it just common sense that to disseminate that type of information to the test taker is not in society's best interest.  Hence, the efforts of the psychological community to restrict the information to the scientific community.  

Please don't misinterpret what I'm saying.  Obviously the tests undergo extensive validation testing, studies are conducted to determine how naive and not-so-naive subjects attempt to manipulate the results, articles are published, textbooks are written, and the information is generally in the public domain.  Nonetheless, many psychological tests assume that the average person taking the test is relatively naive about the details of the test and precisely how it is interpreted.  To the extent that assumption is not met, the validity of the test may decrease.

Does it mean that if the person taking the test were extremely knowledgeable, he'd be able to mislead the psychologist?  I would think it would shift the odds, but would not guarantee success.  A lot would depend upon the forensic psycholgist's skill at administering and evaluating the test, his knowledge of the case facts, his knowledge of the subject's background, and his clinical impression of the subject himself, and his interviewing skills.  

I haven't touched upon the ethics of teaching someone how to manipulate a forensic test.

Peace,

Gordon