Years ago as part of applying for a job (that I did not get), I had to take the MMPI-1 test. I found the questions totally bizarre to the point of being almost impossible to answer. One of the question I still remember was something like, “I have never have any tarry black bowel movements.”
What? True? False? I have no idea. What is a tarry black bowel movement?
There seemed to be an excessive number of questions about bodily functions. Other questions seemed equally irrelevant such as, “I like to read detective novels.” I don’t know how to answer a question like that as either true or false when the real answer is “sometimes.”
I don’t know anything about the new MMPI-2 test, but I given the weird questions on MMPI-1, was it a valid test? What were they trying to measure? And what was the question about tarry black bowel movements about?
The MMPI is a broad personality inventory of fairly long lineage. It provides scale scores for a bunch of different personality “traits” which supposedly fit together to provide the trained observer with a snapshot of your personality, with an emphasis on possible pathologies. It was designed for use as a tool by clinical psychologists, not businesses.
It also includes scales which are designed to measure how truthful you are being. For example, a question might concern some mildly negative behavior, such as nose-picking (not really, but something like that)–supposedly if the person taking the test consistently claims that they never, ever do such things, the test reader should take the rest of their scores with a grain of salt.
It really is pretty useless as a tool for personnel decision-making and was never designed as such. Interpreting it is a job for a trained clinician.
The Minnesota Multi-Phasic Personality Inventory returns a profile of 16 scales. Since it’s a clinical inventory, a lot of the scales measure things like “psychosis”, “depressiveness”, and “hypochondriasis” - in short, the MMPI is mostly looking for things that you don’t want an excess of.
The questions about bodily functions are the most direct way to capture hypochondriacal tendencies - how much do you notice odd aches and pains, how much does it worry you that you might have had a black, tarry stool (are you the kind of guy who examines every poo?)?
A lot of questions, like “I investigate every candidate every time I vote,” are meant to capture a tendency to lie on the test. If the lie scale is too high, this means that you’re obviously trying to create an impression that your a well-balanced, virtuous superman. Some of the lie scale questions are rather odd, and putting the “wrong” answer on a few of these is normal.
The detective novel question is one of many examples of a question that needs more fine-tuning than true or false. This needed fine-tuning is achieved by asking lots and lots of questions. You wouldn’t want to measure paranoia, for example, by asking only one question. But as you ask a lot more questions, you begin to get a picture of how likely a person is to really have some paranoid characteristics.
The MMPI is widely used as a personality inventory because it is highly reliable (you take the test lots of different times, you get similar results) and quite valid (it does do a reasonably good job predicting certain dysfunctional behaviors, such as defensiveness, hostility, sulkiness, etc.).
MMPI 2? This is a bit after my time in psychology, so there may be some important differences.