When you are using information provided by someone else, you are responsible for evaluating that information to make sure it is relevant to your research and objectively accurate. Evaluating information is a complex skill, but learning the C.A.A.R.P. test is a good place to start. C.A.A.R.P. provides you with five factors to apply to each resource:
Currency (Newness): Recently published information is informed by the full range of research on your topic. If two resources are similar, choose the newer one. A good rule of thumb for science information is to look for information that is less than 5 years old.
Authority: If the author is not an expert (has a relevant advanced degree and/or works in that field), the source is less credible. Google the author to try to find their credentials and work background. This technique is called lateral reading and is often used by professional fact-checkers. If you are reading articles written by a professional journalist, look for a journalist who specializes in science reporting.
Accuracy: Is someone other than the author evaluating the information before publication to make sure it is correct and the conclusions the author draws are valid? When your professors ask you to find a peer-reviewed resource, they want you to use an article from an academic journal. These articles are written by experts and evaluated by other experts before they are published. Peer-reviewed articles are easily found using the filters in library databases. If you use any resource outside of a peer-reviewed journal, you will personally need to evaluate the information for accuracy. This can be harder to do if your potential sources do not have a reference list.
Relevance: You want sources that are the best fit for your topic and are written at the right level for what you need. Give preference to articles that focus on your topic rather than just mention it.
Purpose: Be careful about biased sources. You are looking for sources that inform rather than persuade or sell. An easy way to find more neutral sources is to use library databases. If you find yourself getting angry or sad while reading an article, look for language that is meant to evoke an emotion in the reader. Science literature writing should present the facts rather than a point of view. Please consult a librarian if you have any questions.