????1908年，弗蘭克?帕森斯在波士頓開設了世界上第一家職業指導中心。從一開始，他就詢問潛在客戶116個一針見血的問題，內容涉及他們的抱負、長處和弱點（以及他們多長時間洗一次澡）。但他當時還做了一件更加不尋常的事情——他測量了這些人的頭骨。

????帕森斯是一位堅定的顱相學信徒。要是你的額頭較大，他或許會建議你當律師或工程師。但如果你耳朵后的頭骨比較發達，那么你就屬于“動物型”，最適合從事體力勞動。

????令人欣慰的是，職業咨詢自那時起已經取得了長足的進展。但現在，咨詢師不再測量頭腦的外形，而使用心理測試測量頭腦內部已成為慣常做法。個性測試現已發展成為一大產業，是領導力和管理課程的標準程序，它不僅是求職面試流程的組成部分，而且日益成為職業輔導不可或缺的內容之一。但我們是否真的應該相信這類測試能夠揭示出科學且客觀的真相？

????我有一些壞消息要告訴你：即使最復雜的測試也存在很大的缺陷。以邁爾斯-布里格斯類型指標（Myers-Briggs Type Indicator，簡稱MBTI）為例。這種世界上最流行的心理測試的原理是榮格的性格類型理論，它每年大約被應用200多萬次。MBTI測試通過二分法類別——比如你是一位性格內向者還是外向者，你的性情偏重于邏輯還是情緒（也就是它所稱的“思維”和“感覺”）——來判定一個人屬于16種性格類型的哪一種。

????關于MBTI測試有一個非常有趣，也有些令人擔憂的事實。那就是，盡管這種測試非常流行，但30多年來，心理學家對它的批評從未終止過。一大問題是，它顯示出了一種被統計學家稱為低“重測可靠度”的現象。比如說，如果你僅隔5周，再接受一次這種測試的話，你被歸入一個不同于首次測試的性格類別的幾率大約在50％左右。

????第二種批評意見是，MBTI測試錯誤地假設一個人的性格歸屬于相互排斥的類別。你要么是一個性格外向者，要么是一個性格內向者，但絕非兩者的某種混合。然而，大多數人恰恰介于兩者之間。要是MBTI也測量高度的話，你要么被列入“高大”，要么被列入“矮小”，盡管大多數人的個頭都在中等高度區間內。

????結果是，兩個被標為“內向”和“外向”的人的測試分數可能幾乎完全一樣，但由于他們分處一條假想邊界線的兩側，他們或許會被歸入不同的性格類別。

????對于那些認為個性測試可以將他們引入一個完美職業生涯的人來說，還有一件事尤為重要。邁爾斯-布里格斯基金會歐洲獨家經銷商發布的文件顯示，這項測試可以“讓一個人深入了解自己可能會喜歡、并且能夠獲得成功的工作類別。”所以，如果你像我一樣，被歸為INTJ型（也就是說，你的主要性格特征是內向型，直覺感強，偏重于思維和判斷），最適合你的工作包括管理顧問、IT專業人士和工程師。

????When Frank Parsons opened the world's first career guidance center in Boston in 1908, he began by asking prospective clients 116 penetrating questions about their ambitions, strengths, and weaknesses (and how often they bathed). But then he did something more unusual: He measured their skulls.

????Parsons was a committed believer in phrenology. If you had a large forehead, he might recommend you become a lawyer or engineer. But if your skull was more developed behind the ears, you were of the "animal type" and best suited to manual work.

????Career advice has, thankfully, come a long way since then. But now, instead of measuring the outside of people's heads, it has become common to measure the inside using psychometric tests. Personality testing has grown into a major industry and is standard procedure in leadership and management courses, as part of job-interview processes, and, increasingly, in career counselling. But should we really trust such tests to deliver scientific, objective truth?

????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.

????One other thing, and this matters especially for anybody who thinks personality tests can guide them to a perfect career. According to official Myers-Briggs documents published by its exclusive European distributor, the test can "give you an insight into what kinds of work you might enjoy and be successful doing." So if you are, like me, classified as INTJ (your dominant traits are being introverted, intuitive, and having a preference for thinking and judging), the best-fit occupations include management consultant, IT professional, and engineer.