If you are asked to write a piece of coursework or an exam essay on the First World War, you will need to do some research. How can we decide whether a historical source, primary or secondary, is okay to use as reference material? You would evaluate the source. Take this website as an example.

This website is a secondary source about the First World War and is comparable to a textbook. Apart from articles like this one, it also contains:

• First-hand Accounts of the War
• Photographs
• Artwork
• Poetry Animations
• Games

What do this tell you about the website? For example, we can tell by the 'BBC Schools' banner at the top of every page, and by the addition of games mean that the intended audience is younger people studying the topic in school. Does that mean that it is less correct?

Thinking Point: What tells you that it is a useful source? What tells you that it might not be useful? Think about these questions:

• Is it factually accurate? Do the facts and figures match up to other sources?
• Does it present a range of sources?
• Are the conclusions backed up with facts from primary sources?
• Is there anything that the site has left out?
• Is it biased towards one side or the other?
• Does it have other aims besides relating history?
• What is the nature of the company making the website?
• How old is the website?

Some of these questions can only be answered if you do a lot more research into the topic and into the authors. But these are the types of questions you should be thinking about every time you look at a source, whether it is a book, a photograph, a poster, a journal or a film.

Remember that in an essay, even biased sources can be useful if you understand why they are biased. Also remember that no source is completely reliable. Even if it is a first-hand account, you can not assume that it is absolutely true. The best way to find out whether a source is reliable is to compare it to other sources.