Some things to consider when evaluating information sources:
1. Who is the author?
First of all, the author should be identified. The author can be one or more people or organizations.
Is the author credible?
At a minimum, in order to be considered credible, the author of the information source should have credentials and expertise, such as academic degrees and experience, relevant to the topic.
Has this information source been reviewed by experts in the field?
Even authors with credentials and expertise in a field may be biased or may have made a mistake in their research or writing. The most credible information sources are those that have been reviewed and accepted by a group of experts in the field.
2. Who published this information?
The organization(s) that published and/or sponsored the information source should be identified.
Why was this information published?
The most credible information sources are those that have been published in order to present balanced, unbiased coverage of a topic or at least to present both sides of an issue.
The least credible sources are those that have been published in order to promote a certain point of view.
Check the publication for information about the organization(s) that published/sponsored the information source. This can usually be found in the front or back of a printed book or journal, or in the "About Us" or "Mission" section of a web site. You may need to look a little further to determine whether or not the organization has a hidden agenda or whether the author's viewpoints have clouded empirical data.
3. Is the content of the information source relevant for your project or paper?
It should cover the specific aspects of your topic.
It should be up-to-date, if timeliness is critical for your topic. (Check the publication date or, for web sites, the date of the last update.)
It should be well thought out, well presented, and well supported with credible sources.
It should be unbiased. (A bias can be obvious or subtle. It can be hard to perceive a bias if you tend to agree with the arguments presented. If you are uncertain, check with an expert in the field, such as your professor.)