A psychological personality test is a test used to determine whether the person taking it has any of several characteristics, or suffers from any one of a number of psychological conditions.  They are used in by several online matchmaking services to provide valid matches between people of different genders.  The one that comes to mind which advertises that their psychological personality tests can match a person “0n 63 dimensions” is EHarmony.  This matchmaking service makes use of a series of psychological personality tests.  Each person's test is scored, and the people receiving similar scores are allowed to meet.  Many hospitals make use of psychological personality tests to test potential clients for serious conditions like depression, schizophrenia, and paranoia among others.

Another purpose these tests are put to is entertainment.  In other words, people go online and willingly sit through a test designed to measure their personality for fun.  One is left with several questions like:  Just what about taking a test is fun?  Why would a person choose to take a test online designed to measure things like how outgoing they are, or how much they enjoy taking tests and what kind of tests they are good at taking?  I'm not sure what the point is of taking these tests, even though I have been known to get sucked into taking them on occasion.  Usually for me the reason I take this type of psychological personality test is to waste time while seeming to be busy doing something important.

Personality tests are also put to use my people majoring in clinical psychology.  They are used by these students to measure many things, but the point of all their testing seems to be that it's one of the requirements that they need to fill in order to pass the class and receive the degree.

Some of these tests are used to define people in order to exclude them, as some universities use psychological personality tests in order to determine which students to send letters of acceptance to, or to determine which students to house together.  Courts use these tests to determine if the people being subjected to them are violating the law because they have a personality disorder and so merit special treatment.  Marriage counselors use psychological personality tests to determine what is wrong with a marriage and what can be done to fix it.  Debt counselors use this testing to help their clients understand why they are always going over their budget and what they need to do in order to spend wisely.