Something whose existence perpetuates its existence. For those blessed with a sarcastic wit, an excellent phrase with which to describe a sort of evil tautology.

For example, the psychotherapy "industry" seems to be a SelfFulfillingProphecy (see ImNotOkAndYoureNotOkEither).

Here's another one: the whole vicious cycle of the computer/software trade press reporting the analysis of industry analysts, which is informed by the opinion of CIOs, who form their opinions by reading the trade press. This vicious SelfFulfillingProphecy poses a barrier to innovative products trying to penetrate mainstream markets (see CrossingTheChasm).

-- RandyStafford

Another one: when the fashion "gurus" announce what that X, Y and Z are going to be "next year's fashionable colours", it usually happens.

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I find that people on Wiki love to disagree. Don't you agree? ''Yes.'' No. 

''You're both wrong!!!''

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Some of the most common instances are when someone is really scared that something negative is going to happen. They end up reacting to the fear without thinking things through. Often, the reaction directly results in bringing about what it was that the person wanted to avoid in the first place.

Here's an example:
You feel that you cannot accomplish some really desirable goal. You are so convinced that you don't even try. As a result, you do not accomplish the goal. So, the end result is that you have proven yourself correct. If you never try, you cannot accomplish the goal. This is a frequent kind of SelfFulfillingProphecy.

In the above example, if you actually tried to accomplish the goal, you would find out whether the goal was '''actually''' difficult or not. This requires SelfDiscipline to question whether your preconceptions have any real basis or not.

I thought of a more concrete example:
If someone says, "We don't have time to do testing", they won't schedule time for it, or build it in to the development process. To nobody's surprise, it becomes a truism. There will not be time for testing. It's a SelfFulfillingProphecy.

Cheers, -- JasonNocks

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See also CatchTwentyTwo and SelfSealingBelief.