PSC 41 – Lecture 2
Critiquing claims about relationships between variables & steps in critical thinking
- Critiquing claims of relationships between two variables
- Critique (assess claims and make judgements on the basis of well supported
o Access the accuracy (validity) of a claim
- Articulate if a claim is unsupported
o Demand appropriate additional information
- To be critical of something is to appreciate the strengths of the claim and
articulate the weaknesses (if I had more evidence, then I would be convinced)
Steps in Critical Thinking
1. What am I being asked to believe or accept? (This variable is asking me to
believe this variable)
a. Almost every example is an association research making a causal claim
(ex: I’m being asked to believe that there is a causal relationship but we
use association as evidence)
2. What evidence is available to support the assertion?
3. What are alternative ways of interpreting the evidence?
4. What additional evidence would help to evaluate the alternatives (how would you
design a perfect experiment)?
5. Is it true (have they met the threshold to convince a scientific thinker)?
People who eat Champion Cereal for breakfast will be more successful than people who
eat Great Gruel for breakfast.
Claim: Predictor variable cereal choice causes outcome variable success.
There’s a relationship, but there’s no cause yet.
- Evidence: group of people who ate Champion Cereal are more successful than
that group of people who ate Great Gruel.
o Invalid implication: eating causes success, anyone who eats will be more
successful, have to eat it to be successful. - The authors are claiming that a predictor variable leads to an outcome variable
Alternative ways of interpreting the evidence:
- You must accept that the findings are true (must accept that there is a
relationship, can’t dismiss the findings as false)
- You must NOT accept the author’s explanation
o They’re leading you to believe it’s a causal relationship between the cereal
and their success
- 3 variable?
- could there relationship be reversed? (Choose cereal because successful)
Were the groups equal beforehand?
- Can you think of a specific and plausible way that the groups might have been
Work backwards from the outcome variable.
Hint: if the groups were not randomly assigned, then they are almost certainly different
from each other