LibraryEvaluating Websites
Currency
New sites and pages are appearing on the Web constantly. But once they are up, it costs next to nothing to keep them there; updating them is much more costly. So there's a lot of outdated information on the Web. When you're just clicking on search results, though, it's not always clear when the site was made or last revised.
A reputable site will usually show you when it was last updated or include a copyright notice with a year. While this is nice to see, it does not necessarily mean a lot, since the page might simply be made in such a way that it shows the current date when it is viewed.
More important is particular document you will be working with. It should be clear when a particular article, report, essay, chart, etc. was written or last revised.
Even if the information on the site is interesting and relevant to your topic, not knowing when it was written will make it less useful to you. You will not know the context in which it was written, and in some cases the information might simply be obsolete. Many issues, from the environment to immigration to medicine, change frequently, so that you need to know when a piece was written in order to understand its place in your research.
In some fields, older information will not be valuable. A 15-year-old article on global warming will probably not be useful, since our knowledge of the problem has evolved. For other topics, older information may be appropriate.
