 | This help page is a how-to guide. It explains concepts or processes used by the Wikipedia community. It is not one of Wikipedia's policies or guidelines, and may reflect varying levels of consensus. |
 | This page in a nutshell: Sources are rarely plundered for all they are worth, and articles with "citation needed" tags often already have sufficient sources that simply have been under-utilized. Most new sources added for a detail or two can also be dug into for additional sourcing value. |
It is very common for Wikipedia editors to add a citation, such as to a newspaper or magazine article, a book chapter, or other hopefully reliable publication, to source the verifiability of a single fact in an article. Most often the editor has found this source via a search engine, or perhaps even a library visit, seeking a source for a detail in an article, some pesky tidbit without a citation. This common approach, akin to stopping at the grocery store for eggs and milk and nothing else, rather than "working" the store for an hour with a long shopping list and an eye for bargains, tends to miss many opportunities to improve both the content and the sourcing of articles.
This tutorial offers a very short, but real-world example of how to "mine" a source, and really work it like a seam of ore for every last bit of verifiability gold. In addition to noticing facts in your source that are missing from the article, and noticing that your source can also provide a citation for more facts already in the article than the one(s) you were most concerned about, you can also often double-up citations on a fact that already has one source cited. While the average fact in an article does not need seven citations, two rarely hurts, and can provide a cushion if something is found faulty with the other source and it is deemed unreliable, or a third, questionable, source challenges the first.