This page on how to read an article history is intended as an aid to people who are researching with Wikipedia. Experienced Wikipedians often glean a great deal about articles from looking at the page history and following up to the individual edits that make up that history. This page describes some of these tricks of the trade. The suggestions here apply mostly to substantive articles with a number of contributors. If the page history indicates that the page is entirely or almost entirely the work of one person, you are dealing with a situation more comparable to evaluating an article on someone's private web site.
Who has worked on the page
First and foremost, the page history tells you something about who has worked on the page, and allows you to examine the successive versions of the article and the differences between them. Usually by looking through the edit history, you can quickly tell who has made substantive contributions to the article.
If an edit was made by a registered user, you can follow up to their user page to see who they are (or at least who they claim to be). Associated with each user page is an accompanying user talk page, which often gives the flavor of their interactions with other users: is it full of thank you notes or vitriolic arguments? There is also their user contributions page, which lets you look at all the work this particular person has done in Wikipedia, including their side of online discussions with other users.
If the edit was made by a user who was not logged in, you can at least get a look at the other contributions made using the same IP address, which are often, but not always, made by the same user. (Many Internet service providers issue temporary IP addresses to their users from a pool of addresses: when the user disconnects, the address is returned to the pool for allocation to someone else.) Also, it might be a fixed IP address for a computer in a public place such as a library or school; computers in such public settings can show an extreme combination of excellent edits and vandalism, but you still might be able to see that the particular edit came in the midst of a series of edits that help you gauge the character of who was at that machine at that time.
Individual edits in the edit history
Each edit in the article history will contain two links ((cur) and (prev)), the edit date, the editor, and sometimes an edit summary. Sometimes, there will also be an m to designate that a particular edit was only minor. Clicking (cur) will compare the version in question with the current version, while clicking (prev) will compare that version with its previous version. The edit summaries will sometimes assist in explaining the purpose of or the actions within the edit. However, this is optional. Sometimes Wikipedians will often use shorthand to explain their edits. For example, npov and pov mean neutral point-of-view and point-of-view, respectively, cp means copy editing, and rv and rvv both mean revert. See Wikipedia:Glossary for a much longer list of Wikipedia shorthand.
One can usually determine rapidly from the page history whether an article is subject to frequent vandalism. Usually, when an administrator fixes vandalism, the edit summary will be of the form "Reverted edits by Foo (talk) to last version by Bar." In the example given here, the links just go to the Wikipedia sandbox, but in the real case they will take you, respectively, to the user contributions page and the talk page of the person whose content was reverted. While this form of edit summary is not always a reversion of vandalism, that is what it will be at least nine times out of ten: reversions for other reasons will almost always get a different summary, explaining the issue at hand.
When a contributor who is not an administrator reverts vandalism, the edit summary will typically be just "revert vandal" or "rv"/"rvv" for short.
Note that very occasionally edit summaries may falsely claim to be reverting vandalism when something else is actually going on. You can always look at the actual "diff" to see exactly what was changed by the edit.
But, of course, as a researcher, you are more interested in identifying current, uncorrected vandalism than just the fact that the page may have been vandalized and fixed in the past. While there is no surefire way to spot such things, you should look for—and look at—very recent edits by someone who has made no positive contribution to the page in the past, and/or edits attributed only to an IP address. If such edits exist, you will almost certainly want to examine those edits to see if they are suspicious, especially if there is no edit summary to explain what is going on. You can usually tell by a bit of examination of the article history when was the last time someone took a look through recent work and cleaned up any recently introduced problems.
Identifying edit wars
One can usually determine rapidly from the page history if an article is, or has been, the subject of an edit war. In an edit war, two users (or sometimes two groups of users) are editing alternately; if you "diff" between successive versions of one side's edits, the article is repeatedly restored to more or less the same state; and examination of the difference between successive indicates that this is not simply one or more solid contributors fighting off vandalism. Usually, one can quickly tell from the edit summaries that there has been a genuine disagreement over content. For example:
- (cur) (prev) 13:36, January 27, 2006 Mik (No *rational* arguments in Talk yet,)
- (cur) (prev) 13:30, January 27, 2006 Reb (revert to consensus first paragraph for now)
- (cur) (prev) 13:03, January 27, 2006 Mik (Reb's POV removed; neutral-tone version restored.)
- (cur) (prev) 11:55, January 27, 2006 Reb (revert pov pushing)
- (cur) (prev) 11:29, January 27, 2006 Mik (See Talk. Alternate source of Resolution linked.)
- (cur) (prev) 10:10, January 27, 2006 Reb (remove misleading 2nd paragraph)
- (cur) (prev) 04:03, January 27, 2006 Mik (the coup)
In a case like this, if these are the latest edits, a researcher will almost certainly want to examine both versions. There is clearly a thread of argument over something substantive.
Sometimes this can also be clarified by having a look at the talk page, where the contributors to the article often carry on discussion in far more detail than would fit in edit summaries. In the example above, one would hope that Mik and Reb have both stated their case, and perhaps others have also weighed in.
One very good measure of article stability is to compare a version from a month or two ago to the current version. Unfortunately, Wikipedia's comparison tool sometimes fails to line up the correct paragraphs with one another, and articles that have had little more than spaces removed can seem at first glance to have massive changes. Hence, while this tool can quickly confirm that an article has not had major changes, but where it appears at first glance to show major changes, you will need to follow up carefully to see whether this is, indeed, the case.
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