Evaluating Evidence

What does evidence need in order to be “good”? Ask yourself these questions when evaluating your sources?

Is my source reliable and credible?

This means your author has some expertise or knowledge in the field. Arguments are backed up with facts and analysis. The article is published through a reputable publication or is peer-reviewed.

Does the source have some empirical basis?

Your source should base its claims on broad observations and facts rather than cherry-pick evidence to make an argument.

Does the source make a claim?

Is the information provided important to the topic or my case specifically? If yes, then the article is worth reading.

What is the source’s bias?

Saying a source is “biased” is a favorite evidence attack. The fact of the matter, however, is that every piece of evidence you will read will be “biased” in some way because it comes to a conclusion that excludes other conclusions. Bias is not inherently bad; the connotation of bias, however, is negative. This is because there are two types of bias that are often conflated.

Bias as prejudice:

If the author makes a claim based on pure opinion or prejudice, then the bias undermines the validity of the claim. Here bias comes from a person’s opinions or personal perspective on the world, meaning that their conclusions are filtered through their personal lens. In order to prove their argument they must disregard information or evidence that could prove the argument wrong. Prejudice leads to a conclusion regardless of the available evidence. You should always be able to defend the conclusions your evidence contains. These conclusions should be shared by others of different perspectives and should not be conclusions that one individual or group has reached.

Bias as informed opinion:

If the author has gathered years of expertise that leads the author to conclude one side of an argument is stronger, that bias is defensible. Here, bias is not a negative thing. If a source’s experience and research has led them to a conclusion, you should be able to weigh this evidence against conflicting evidence. Like a golfer has to adjust his or her swing to deal with the wind, adjust your presentation of the evidence to deal with refutations.