In this guide, we’ll be discussing some ways to evaluate the relevance and credibility of evidence used in an argument. This guide isn't meant to be comprehensive (otherwise we'd be here all week), rather to get you started thinking critically about the arguments you read, write and hear.
Definitions and Information come from page 20 of the AP Research CED.
First, let's clarify: What is evidence?
Evidence is actually quite a broad category: it's anything used to support a claim. Really, anything! Evidence can be facts and data as one would expect, but it can also be observations, predictions, analogies, explanations, and opinions. For example, my analogy about eating Hawaiian Pizza from the 2.2 guide counts as evidence, because I'm using it to back up a claim.
Whether or not a piece of evidence is good is different from whether or not it's evidence.
How do we tell if a piece of evidence is good? Let's start by looking at the context and situation of the argument it's being used to support.
According to the College Board, an argument’s context (time and purpose) and situation (in relation to other arguments) inform its interpretation.
Time refers to when, historically speaking, an argument was written. An argument written a hundred years ago, for example, is going to have a different set of underlying assumptions and evidence to work with than the arguments that are written today.
This means that time also matters when analyzing the evidence used to back an argument. Is a certain statistic outdated, for instance? (Has another study proven that statistic false or inaccurate?) Does a certain assumption presuppose that everyone reading is of a certain gender or faith, or make assumptions that have since been disproven? Outdated evidence can sometimes invalidate a whole argument.
Purpose refers to what an argument was written to do. Does this argument want you to do something? Buy something? Ask something? Is this argument meant to support a certain ideology?
This is important for the analysis of evidence because authors strategically use evidence to support their claims to meet their overarching purpose. If you're making an argument, you're not going to use evidence that directly counters that argument (unless it's part of a counter-argument section). Therefore, the evidence you're being presented with might only be one side of the story.
Situation refers to the position of an argument in relationship to other arguments. Academic papers are all part of a larger academic conversation, with multiple competing arguments that it has to interact with. (Your final paper will be the same! It'll interact with the papers that other people have been writing.) A funny way to think of this is to ask: If this paper were a tweet, who would it @?
Now, let's take a closer look at the evidence itself. Not every piece of evidence is credible. Before you use a piece of evidence, check its sourcing, or where it comes from. Could the source be so biased that it can't be trusted? Does the source have the authority and research to be making the claim it does?
It is also important to be on alert about potential data misrepresentation. Sometimes, writers may brush over weaknesses in their evidence by not representing it 100% accurately.
A statistic may be used in a way that doesn't represent what it actually says. For example, a 100% increase in success rate sounds amazing, but if it's just a jump from 1 success to 2 successes... not so much.
If you're using scholarly articles from scholarly databases, the sources they cite should be reliable. However, that's not always guaranteed. (If you have time to spare, check out this amazing documentary series
about a scandal in the scientific world.)
After you look at the context and credibility, it's time to look at what a piece of evidence is doing for the argument. How does it support the claim the author is making? Good authors will generally explain the implications of a piece of evidence; it's what we're taught to do with the Claim-Evidence-Reasoning structure of argumentation. If there isn't this explanation, or you don't agree with it, look deeper. The evidence might be credible but not used well. That can happen.
What can evidence do? Here are some purposes of evidence, with 100% made up examples.
Identify relationships ("According to the National Association of Pizza Lovers, approving of pineapple on pizza is correlated with good grades…"🍍)
Explain relationships ("Experts suggest this is because people who are open to putting pineapple on pizza have an open mind to explore new food combinations, which may correlate to being more open minded learners...)
Identify trends ("In 2022, statistics from the Pineapple Lovers' Association indicate that pineapple sales have gone up by 15%.")
Explain trends ("Because of the increase in restaurants that put pineapple on pizza, the pineapple economy has done better than last year.")
We've covered some ways to start thinking critically about evidence. Please keep in mind that you don't have to subject every piece of evidence you use to this rigorious analysis. Statistics, for example, can often be confirmed by a quick double-check that they aren't outdated.
In the next guide, we'll be looking at the implications of conclusions.