There seems to be a bit of misunderstanding about the purpose and intention of this test, and the Myers-Briggs type system. I'm by no means an expert, but I know enough about the system to see there are some knee jerk misunderstandings going on here. So feel free to correct me if I get anything not exactly right, but this should raise the level of discourse on this subject a bit I hope.

To talk intelligently about the results of the test, you must first understand the vocabulary they are using. That vocabulary is more technical than the common understanding of the words that are used to name the categories. This test, love it or hate it, was created by people in the sciences, and the categories, whether useful as predictors or not, have specific definitions.

The M-B test is centered around four behaviors [(N|S)(F|T)] and two attitudes [I|E]. The attitudes are perhaps the most commonly misunderstood, because we have strong natural usage around the words extrovert and introvert that is quite different from the technical definition in the M-B system. For starters, it is probably safe to just think of these as modifiers on the behaviors, such that an extroverted behavior is directed out to the world, and an introverted behavior is directed towards your mental life.

Of the four behaviors [(S|N)(T|F)], two behaviors function to Judge the world (Thinking, Feeling) and two behaviors function to Perceive the world (Sensing, iNtuiting). Feeling is another misunderstood one. While it includes "emotional" decisions, it also includes "going with your gut".

The least obvious piece of the system is how the four letters interact. Lets take INTP, since for once, we are the majority here, and it is mine, so I can use myself as the subject to discuss rather than the obnoxious "If one is a ... than he/she..."

What these four letters do (yes, in theory) is establish my PREFERENCE for these behaviors. From INTP, my core type is NT or Rational (according to Keirsey). I prefer to perceive through iNtuition, and decide through Thinking.

The I and the P are modifiers on those types. The P tells me that, when interacting with the world (in my Extraverted attitude), I prefer to be in a Perceiving behavior. The [I] tells me that, all other things being equal, I prefer to be in an Introverted attitude.

The primary piece of M-B theory that I find interesting and worthy of debate is this: A person has a primary Perceiving and Judging behavior, and they tend to prefer to use one in an Extraverted attitude and the other in an Introverted attitude.

This implies that, since I prefer to use my Perceiving behavior (iNtuiting) in my Extraverted attitude, I prefer to use my Judging behavior (Thinking) in my Intraverted attitude. This is the difference between an INTP and an INTJ.

So, M-B would say my two main behaviors are Ne and Ti. Ok, now let's deal with the [I]. This tells us which, of the two attitudes I prefer. So, according to M-B:

My primary behavior is Ti

My secondary behavior is Ne

My terciary behavior is S(i) (sometimes i is not shown)

My inferior behavior is Fe

One actionable result for me from taking this test has been that it reminds me that I have a tendency to under use my extraverted feeling decision maker. Which I have found to be true, and so I make sure to consciously bolster this response when the opportunity to use it presents itself.

In closing, it is crucial to remember that this test determines PREFERENCES. It says NOTHING about ability or correctness. If you have Judged Thinking better than Feeling, or think you can perceive more by Sensing than iNtuiting, than you are probably out of touch with your other behavior. I believe that we should all strive to be very balanced on this test.

However, I do agree with M-B theory that people do have a tendency to gravitate to the poles, often because of strength or social culture. I believe one of the best uses of this test is to recognize which behaviors you prefer, and also recognize the ones that you could benefit from giving more attention.

Thanks. :)

edits for clarity and such