When you talk about a source's relevance, you need to explain how useful the source is in answering the topic under investigation. To help you determine a source’s relevance, ask questions such as:
Demonstrating source relevance in your writing:
Pliny’s account is particularly relevant to the issues of public entertainment in Roman society and Roman attitudes towards gladiators because he witnessed many such events firsthand.
Marx’s theory of surplus is a useful model to describe the problems of capitalism that arose in renaissance Europe because he drew upon many social conflicts that were evident he observed.