Why does it exist?

After considering who is responsible for a source of information, the next most important thing to consider is why the information exists. Sometimes this will flow logically from the question of who wrote something, but sometimes it takes a bit more thinking about. 

Information can be provided to persuade the reader. Perhaps it is provided by a company selling a product – of course they will claim that their product is the best! Or perhaps it is from a political party or a pressure group, wanting to get you to take their side in a subjective argument. Persuasive writing can be very good, but you might need to make sure you balance it by reading something which is written from another perspective. 

It can also be provided to entertain the reader. There’s nothing wrong with that, but something written to entertain may not be particularly accurate, or may miss out details which are important, but considered “boring”. If you want a quick introduction to a topic, that’s OK, but for preparing an assignment, it’s probably best to find another source. 

A lot of the information sources which you use at university will have been written to inform or educate the reader. This is often the best sort of source to use. However, it is worth thinking about how “deep” the information goes. In the same way that you need to think about your own writing and what it achieves, think about what you are reading. Does it describe something, does it explain something, does it critique something?  

If you think that perhaps what you are reading is not quite right (perhaps it is a very general description of a topic, for example), you might be able to follow links or references from it to other sources of information which are more detailed. For instance, many Wikipedia pages have links to academic books, journal articles and other sources where you can read more detailed information written by the experts.