|This is an essay. It expresses the opinions and ideas of some Wikimedians but may not have wide support. This is not policy on Meta, but it may be a policy or guideline on other Wikimedia projects. Feel free to update this page as needed, or use the discussion page to propose major changes.|
Wikipedia is not a prediction market or futurist club, but some articles regarding an important event must deal with its predicted effects as of some date.
Before an event occurs, it has only predicted effects. After it occurs, it has alleged effects observed in reality, but, it still has predicted effects that can be compared against the alleged effects - the two diverge the instant the event occurs. Usually, alleged effects can be dealt with in the main text of articles. Predicted effects that were predicted in advance, however, should be concentrated in their own articles. Therefore, it makes sense to do this from the beginning. As an example, see the en:predicted effects of invading Iraq. This gathers in one place all that we could find about the debate on that subject, and prevented spreading such predictions into many articles where it would be hard to dig them out. So such articles should probably exist for all globally important decisions.
More importantly, having this list, makes it much easier to write neutrally about which effects were anticipated, and which were surprising. After the event, articles about "what happened" should be able to compare the predicted effects to the alleged effects, to determine, among other things, what was a well-understood risk, and what was poorly understood or over-estimated or under-estimated, by both advocates and detractors of the decision.
One can freely modify "predicted effects" before the fact, but afterwards, only with strict and trustworthy references to prove those were predicted beforehand. "Alleged effects" can continue to be freely modified, and, predicted effects that do not occur can be made note of. The page history of the article on predictions makes it easy to see which predictions were clearly stated in advance of the event. This drastically simplifies validation that a prediction really existed beforehand, and that allegation matches prediction.
The naming of the anticipated or feared event is a great risk of hastiness and bias. A major figure who can actually make the decision to do something (invade, subvert, ignore a regime, cut it off from aid, give it weapons) should be widely reported to be seriously considering it before we bother to create any list of "predicted effects". Some are long term like predicted effects of colonizing Mars, others short term like invasions.
At any one time, there will be hopefully no more than three or four of these articles listing predictions going at a time, for huge geopolitical and scientific events (say as another example en:predicted effects of cheap fusion power), but no more than that. Unless there is a great deal of speculation and prediction going on, and some clear future event at which point one can separate prediction from allegation, it's better to simply note in articles that "Predicted effects of..." exist. That makes it easy to find the predictions if a whole article of them must be assembled later.
See also: en:Wikipedia:as of