Welcome to Assessing Inferences!

In the "Using Evidence" section of your Thinking Skills course, you have already looked at how to check if evidence is credible (believable). Now, we are moving to the next level: Assessing Inferences.

An inference is a "logical jump" from a fact to a conclusion. For example, if you see someone carrying a wet umbrella (Evidence), you might infer that it is raining outside (Inference). Assessing an inference means asking: "Is that jump safe, or are we leaping into the dark?"

Don't worry if this feels a bit abstract at first. By the end of these notes, you will be able to spot a "weak jump" from a mile away!

What is an Inference?

An inference is a conclusion drawn from evidence. It isn't explicitly stated in the evidence itself, but it is what the evidence suggests is true.

When you assess an inference, you are judging how strongly the evidence supports that conclusion. Does the evidence make the conclusion certain, probable, or just possible?

Quick Note: To learn how to create your own inferences, see the chapter "Suggest inference from evidence." In this chapter, we focus only on judging inferences that someone else has already made.

The "Strength" Scale

In your exam, you will often need to decide if an inference is "overdrawn" (going too far) or "well-supported." Think of it like a bridge:

  • A Strong Inference: The evidence provides a solid foundation. There are very few other ways to explain the evidence.
  • A Weak (Overdrawn) Inference: The evidence is thin, and the conclusion is huge. The bridge is likely to collapse!

How to Assess an Inference: Step-by-Step

1. Identify the Evidence and the Inference

Before you can judge the link, you must be clear on what the two parts are.
Example: "The suspect’s fingerprints were found on the broken window (Evidence). Therefore, the suspect definitely broke into the house (Inference)."

2. Look for "Over-Inference"

This is the most common flaw in Thinking Skills scenarios. An inference is overdrawn if it claims more than the evidence allows. Look out for "absolute" words like all, every, never, definitely, or must.

Example: "Sales of ice cream rose in June (Evidence). This proves that ice cream is the only thing people like to eat in summer (Inference)."
Assessment: This is an over-inference. The evidence only shows a rise in sales; it doesn't support the claim that it is the only thing people like.

3. Consider Alternative Explanations

Could the evidence point to something else? If there are other plausible explanations, the inference is weaker.

Example: "A student failed their math test (Evidence). They must have been lazy and didn't study (Inference)."
Assessment: This is a weak inference because there are alternative explanations: the student might have been ill, the test might have been unfairly difficult, or they may have had a family emergency.

4. Check for Correlation vs. Causation

Just because two things happen at the same time (\(A + B\)) doesn't mean one caused the other (\(A \implies B\)).

Did you know? There is a famous (but silly) correlation between the number of pirates in the world and global warming. As the number of pirates decreased, global temperatures rose.
The Inference: "Pirates keep the earth cool."
Assessment: This is a poor inference because it confuses correlation (two things happening together) with causation (one thing causing another).

Key Terms to Use in Your Answers

When writing your assessment, use these command words and terms to sound like an expert:

  • Supported: Use this if the evidence makes the inference likely.
  • Overdrawn / Over-stated: Use this if the inference claims too much (e.g., claiming "certainty" when the evidence only suggests "possibility").
  • Consistent with: Use this if the evidence could mean the inference is true, but doesn't prove it. (e.g., "The fingerprints are consistent with the suspect being at the scene, but do not prove they committed the crime.")
  • Speculative: Use this if the inference is just a guess with very little evidence to back it up.

Common Mistakes to Avoid

Mistake 1: Bringing in outside knowledge.
Only assess the inference based on the evidence provided in the text. Even if you know a "fact" from your own life, if it isn't in the stimulus material, don't use it!

Mistake 2: Confusing "Plausibility" with "Support."
Just because a conclusion sounds like it could be true (plausible) doesn't mean the specific evidence provided actually supports it.

Mistake 3: Forgetting the "Maybe."
In Thinking Skills, we rarely deal with 100% certainty. If you are asked to assess an inference, often the best answer involves explaining why the evidence partially supports it but falls short of proving it.

Quick Review: The Assessment Checklist

When you see an inference in Paper 2 or Paper 4, ask yourself:

  • Does the evidence directly relate to the conclusion?
  • Is the conclusion too extreme (using words like "always" or "totally")?
  • Are there other reasons why this evidence might exist?
  • Is this just a coincidence (correlation) rather than a cause?

Key Takeaway: A good assessment of an inference identifies exactly how much of the conclusion is supported and identifies where the "jump" becomes too big to be logical.

Note: For more on how to deal with conflicting evidence, check the chapter on "Develop, articulate and justify a judgment based on multiple sources."