In most cases, you should look for sources published in the last 5-10 years, unless your assignment requires older materials. This may vary depending on the subject - for example, with health-related information, you might really need to focus on the last 5 years.
You might also ask your professor if there are any older sources that are especially important to your topic.
Special considerations for...
Books
- Because of their length, books require much more editing and planning than other materials. They take longer to publish, so they may not have the most current information.
Articles
- Scholarly and professional journals often take months to publish something after it's been submitted. They will may not have the most current information either, but they make up for it in level of detail.
- Newspapers and some magazines try to publish information about current events. They should be good sources for the most current information.
Websites
- While blog entries and online articles often include a published date, it can sometimes be hard to tell when other websites were published or updated. If you can't find a date on the website, you may want to use a different source.
Social Media
- Social media is a great place for people to share information about current events as they're happening, as well as people's opinions about those events. Tagged posts can make it easier to find a lot of different sources on the same topic.
- On the flip side, it may be hard to find older social media posts, about less-than-current topics. (ex. the 2012 or 2016 U.S. presidential elections).