This article at VOX points out numerous problems with the test. Erika Price, a friend of mine who has a Ph.D in psychology (and who has written articles for this website), summed up the criticisms as follows:

-Myers-Briggs is based on an old, fringe, untested hypothesis -The categories do not naturally occur in any sample data -The test itself was formulated by people with no psychometric training or experience - It divides people into categories when really every trait is a spectrum - People are divided into binary categories even though most people are near the middle of the spectrum. -Individuals do not consistently get the same type. (i.e. it is unreliable) - It does not predict behavior -It is not used in mainstream psychological research

It's 2014. Thousands of professional psychologists have evaluated the century-old Myers-Briggs, found it to be inaccurate and arbitrary, and devised better systems for evaluating personality. Let's stop using this outdated measure — which has about as much scientific validity as your astrological sign — and move on to something else.