Reverting is reversing a prior edit, in whole or in part. Revert vandalism upon sight but revert an edit made in good faith only after careful consideration. It is usually preferable to make an edit that retains at least some elements of a questionable prior edit than to revert it entirely. Your bias should be toward keeping as much of the prior edit as possible.
Reverting drives away editors
Reverting tends to be hostile, making editing Wikipedia unpleasant. Sometimes this provokes a reciprocal hostility of re-reversion. Sometimes it also leads to editors departing Wikipedia, temporarily or otherwise, especially the less bellicose or the inexperienced. This outcome is clearly detrimental to the development of Wikipedia. Thus, fair and considered thought should be applied to all reversions given all the above.
Good reasons to revert
The main purpose of reversion is to undo vandalism or other disruptive edits. If you see an edit that you're sure was intended by its author to damage Wikipedia, and it does, there is no need for further consideration. Just revert it.
In the case of a good faith edit, a reversion is appropriate when the reverter believes that the edit makes the article clearly worse and there is no element of the edit that is an improvement. This is often true of small edits.
Whenever you believe that the author of an edit was simply misinformed, made a mistake, or did not think an edit through, go ahead and revert. If that editor (or anyone else) re-reverts, you will know it is more than that, and you should be more conservative in deciding whether to revert it again.
Another kind of acceptable reversion is an incidental one. A Wikipedia editor is not expected to investigate the history of an article to find out if an edit being considered is a reversion of some prior edit. The rule against reversions applies only to cases where the reverter is aware that the edit is a reversion of another edit.
Bad reasons to revert
There are a number of things that sometimes motivate an editor to revert, but should not.
- Do not revert unnecessary edits (i.e., edits that neither improve nor harm the article). For a reversion to be appropriate, the reverted edit must actually make the article worse. Wikipedia does not have a bias toward the status quo (except in some cases of fully developed disputes, while they are being resolved). In fact, Wikipedia has a bias toward change, as a means of maximizing quality by maximizing participation.
- Even if you find an article was slightly better before an edit, in an area where opinions could differ, you should not revert that edit, especially if you are the author of the prior text. The reason for this is that authors and others with past involvement in an article have a natural prejudice in favor of the status quo, so your finding that the article was better before might just be a result of that. Also, Wikipedia likes to encourage editing.
- Do not revert a large edit because much of it is bad, and you do not have time to rewrite the whole thing. Instead, find even a bit of the edit that is not objectionable and undo the rest. (To do this, you can use the "undo" button, then type or copy back in what you want to keep). If a supporter of the reverted edit wants to save more of it, that editor can re-edit in smaller pieces and the article can converge on a consensus version that way.
- Reversion is not a proper tool for punishing an editor or retaliating or exacting vengeance. No edit, reversion or not, should be made for the purpose of teaching another editor a lesson or keeping an editor from enjoying the fruits of their crimes.
- Do not revert an edit as a means of showing your disapproval of the edit summary.
- Do not revert an edit because you need more time to determine whether you agree with the edit.