Information is relevant when it helps you to answer your research question. You assess the information on the basis of format, content and degree of up-to-dateness.
This refers to how sure you can be that the information is correct. How credible is the information? How objective is the information? There are several aspects to take into consideration when you are assessing how reliable your information is. These aspects relate to the origin of the information as well as its quality.
Does the information relate to your research question and the aim of your research?
Ask yourself the following questions:
If you are conducting academic research into depression, an article from Cosmopolitan or Hello! will not provide information of the standard you require. Articles from academic journals are more appropriate. (See the chapter Choosing information sources)
Which publications are most suitable depends on your information requirement. I.e. if you need current, in-depth information on a topic it is better to consult recent journal articles in stead of a handbook. And in preparation for writing a light-hearted article for Rolling Stone you are probably not going to study a monograph.
The term ‘current’ usually refers to recent events or developments. In order to determine whether information is current, check whether it still reflects the present situation. A book or article that was not written recently may still be current.
Usually current information is required, but not always. The importance of this criterion depends on your research question.
How complete is the information you have found?
Are you sure you haven‘t overlooked any relevant information? Have you considered all points of view? Although being comprehensive is usually not possible and at this stage in your academic career not strictly necessary, you should always try to be as complete as possible in the literature you are using for your research.