Knowing when your material was published is very important when evaluating it. Topics in rapidly changing areas such as medicine, computing and technology often demand very current information which you find in recently published books, journal articles or on the Internet.

In some subject areas such as art, history, or literature, information published 5 or 10 years ago is often just as valuable.

To decide how current your material is, look at:

• the publication date of the book or journal article
• the dates of the references listed in the book or article's bibliography
• the date that the web page was last updated
• If you cannot find these dates, you will have to use other ways to evaluate the information.

Be aware that dates can be misleading:

• Books - It can take up to two years for a book to be published, so the information in a 1999 book may already be out of date. Some dates represent the year a book was republished (as a paperback, or after being out of print for some years).
• Journals - Journal articles are usually printed more quickly than books, but there can still be a delay of over a year (depending on the journal) before you see it.
• Web pages - Many are updated constantly, but there is no guarantee that the date given (if given at all) is accurate.