Publication Date

Tutorial Directory
MM Companion

Date: How Recently Was the Page Published or Updated?

The 'currency' or 'freshness' of the information may be vital to your search. If you are looking for statistics, news about terrorism, or current scientific research, information published in 2007 may not be as reliable as data from 2015.

On the other hand, if you are not seeking time sensitive information, the date of publication may not be as important when determining credibility.

Remember: much of the time information on the Web is never updated after it is published. The information could be fresh or it could be stale. It is up to the searcher to decide if the date of publication is an important element in the search.

Determining when a web page was created or updated

Best: Publication Date. Sometimes the page content will include dates, or references to dated materials. These 'content dates' may be the best indicator of currency.

Second Best: Last Modified. A date that is associated with a revision may have to do if there are no other dates available. Look at the bottom of a web page to see if the author has indicated when the page was last updated. Authors and webmasters typically put copyright, revision and update information at the bottom of the page. Metadata can reveal last update information, although this may be tricky to interpret.

Third Choice: Copyright. Find a copyright date that reveals the year the page was posted. This date is usually at the bottom of the page. The trouble with copyright is that it may be updated while the content is not.

What does 'updated' really mean?

Many Web page authors display the date when a page has been updated. This gives the searcher some idea of how fresh or current the information is. However an update may be as simple as a font change, a spelling fix, or the addition of a new link. It cannot be assumed, based on a modification date alone, that the content of the page has been significantly revised. The date is just one element in the evaluation of a Web resource.

Example: This Day in History: July 27. Near the bottom of the page is all the information needed to cite the page, including original date of publication, authors and last modified date.

Methods to detect the date of a Web page

Some Web pages have no obvious date: no copyright, revision or timestamp. In such cases, finding publication information requires investigative searching to determine publication date information.

There are technical methods to help you find out the date that the page was last changed on the server. When you can't find copyright, revision, or update information, these methods can be useful. However, it is important to understand that the modification date will change when even a minor tweak is made on the page.

Finding Modification Dates using Metadata

Copy and paste the following code snippet into the omnibox to retrieve Last Modified information for any .htm or .html Web page:


If used on another type of Web page (e.g, .asp or .php or .pdf, etc.) the information will appear to be immediate--the time when the search was conducted. It doesn't mean the page was recently modified--it is simply the time the command was executed.

Other methods for finding the last modified date of a static Web page include:

  • Browser tools: For example, using Firefox, right click on a page to be investigated and select View Page Info. The Last Modified information is display in an alert box. If you are using Firefox, try it on this page.
  • The Metadata Search Wizard on this site includes ways to retrieve a variety of HTTP header information for any page, including Last Modified data (if provided).
Demonstration using the Digital Library Research page

When this demonstration was conducted (Dec. 5, 2018), at the bottom of the page was a statement that the page was last updated on April 29, 2002. Sixteen years is a long time--how reliable is this information? Entering the page URL in the Metadata Wizard retrieved a more recent date: May 9, 2013. So the page content IS more recent than 2002. But it's impossible from this alone to tell what is different than 2002.

An additional step is to look up archived copies of the page. Using the Wayback Machine on it is possible to see the page as it looked on April 1, 2002. Comparing the two pages, the page hasn't changed substantially in 13 years. This raises a concern about the freshness of the information. In fact, a number of the links on the page are dead.

Technical methods of determining publication date are useful, but not as accurate as a printed copyright date. If the content contains a credible date, it may also be a better choice than this server modification method.

Web 2.0 and Dates

The Read-Write Web, while authorship can really be questionable, has distinct advantages over static Web pages when it comes to pinning down publication dates. Whenever someone posts material or a comment, a timestamp is created and printed.

Example: Google Blog. The dates were not put there by the authors but by the authoring software.

Page Properties

If a .pdf, .doc or other type of file is lacking a printed date, it is possible to check metadata by looking at page Properties.

Example: How digital tools prepare students for the 21st Century. This PDF doesn't display an obvious publication date. To find the metadata, download [] the document from the Web and open it in Acrobat Reader or Pro (it doesn't need to be saved). From the File menu, open Properties. The created and modified dates are both displayed: March 30, 2009.

Web Search

In cases where no date information is available on the page or metadata, it may be possible to find another copy of the page or a reference to the page that includes a date citation. Use clues as queries: search for identifying characteristics: title, author, keywords, file numbers. Many times these are found in the URL.

Example: Ramadan and Diabetes. This page doesn't contain a publication date. One method is to search for the URL to see who links to the page. They may have cited it. That doesn't turn up a definitive date in this example. However, there are clues on the page that help date the document. There are links to pdfs and ppts that can be dated. One of these is guidance for Imams which was authored in 2015, so the page can't be any earlier than that. Another link to a pdf has a creation date of 2017, and a ppt is dated April 2017, so the page can't be earlier than that. While this doesn't provide solid evidence for a date citation, it does help establish that this information was authored after April 2017 and before December 2018.

A check of the URL on can provide more information. According to the archive, various forms of this page have existed since 2014. The current content is essentially the same as it was on April 21, 2017. If a citation is necessary, that date could be used.

MM Companion

If all else fails...

Sometimes you simply can't find the date of a resource. All citation formats make allowances for this ranging from (n.d.) no date to citing the date the resource was retrieved online. Unless establishing the date is highly important to your work, once you've done due diligence using techniques to track down a date for a resource, and you still want to use it, it is acceptible to cite the day you retrieved it. That's the recommended approach for the Ramadan and Diabetes example above.

Authored by Lora K. Kaisler and Dennis O'Connor | revised 2018 by Carl Heine