Relevance is the extent to which the information contributes to answering the research question. This includes both main, partial and search questions. You assess the information and sources of information found according to content, form and topicality.
Content and level of information
Connection of information to question and purpose
Form of information
Does the type of information source (book, article, dissertation, etc.) fit your information needs?
If you are looking for background information, you may be better off consulting a book or website than reading an in-depth research article. For writing a lighthearted article in Folia, you will not be so quick to study dissertations (see choose sources of information).
Topicality
This word is usually used for recent events or developments. To determine if information is current, you look to see if the information from a particular year is still true to the current situation. Sometimes certain information does not change. An older book or article may still be current. Publications that continue to hold their value are called core publications. Usually it is important to find current information, but not always. A historian will mainly look for old, often not current information. So it depends on (research) question and purpose.