The Rorschach Test
Most people have heard of the Rorschach test (pronounced "ror-shock"), but few have ever seen a real Rorschach inkblot. The blots are kept secret. When you see an inkblot in a popular article on the test (as in the Encyclopaedia Britannica entry on the Rorschach test), it's a fake: it's an an inkblot, but not one of the inkblots. There are only ten Rorschach inkblots.
Psychologists want the blots to remain a secret from the general public so that reactions to the blots will be spontaneous. Hermann Rorschach hoped these spontaneous reactions would yield valuable clues to the test subject's personality. Whether they do remains controversial. Many psychologists think the Rorschach test is hopelessly unreliable; others see it as one of the cardinal tools of modern psychodiagnosis. Even among those who acknowledge the value of the test, there is disagreement on interpretation of responses.