Is the Myers–Briggs Type Indicator reliable?

I have some bad news for you: even the most sophisticated tests have considerable flaws. Take the Myers–Briggs Type Indicator (MBTI), the world’s most popular psychometric test, which is based on Jung’s theory of personality types. Over two million are administered every year. The MBTI places you in one of 16 personality types, based on dichotomous categories such as whether you are an introvert or an extrovert, or have a disposition towards being logical or emotional (what it calls “thinking” and “feeling”).

The interesting — and somewhat alarming — fact about the MBTI is that, despite its popularity, it has been subject to sustained criticism by professional psychologists for over three decades. One problem is that it displays what statisticians call low “test-retest reliability.” So if you retake the test after only a five-week gap, there’s around a 50% chance that you will fall into a different personality category compared to the first time you took the test.

A second criticism is that the MBTI mistakenly assumes that personality falls into mutually exclusive categories. You are either an extrovert or an introvert, but never a mix of the two. Yet most people fall somewhere in the middle. If the MBTI also measured height, you would be classified as either tall or short, even though the majority of people are within a band of medium height.

The consequence is that the scores of two people labelled “introvert” and “extrovert” may be almost exactly the same, but they could be placed into different categories since they fall on either side of an imaginary dividing line.

Chosen excerpts by Job Market Monitor

via Have we all been duped by the Myers-Briggs test? – Fortune Management.