Watson-Glaser Critical Thinking Appraisal Evaluating Causal Relationships 5 — Questions and Answers
Question 1: A company introduces mandatory ergonomic chairs and reports a 25% drop in employee sick days the following quarter. The CEO attributes this to the chairs. What additional information is MOST critical before accepting this causal claim?
- The cost per chair compared to prior office furniture.
- Whether sick day rates followed the same downward trend company-wide in prior years or industry-wide at the same time. (Correct answer)
- How many employees expressed satisfaction with the new chairs.
- Whether the chairs come with a manufacturer warranty.
Correct answer: Whether sick day rates followed the same downward trend company-wide in prior years or industry-wide at the same time.
A preexisting downward trend or a seasonal/industry-wide reduction would suggest the drop was not caused by the chairs.
Question 2: Which of the following pairs of events is the BEST example of a spurious correlation (both caused by a third factor, with no direct causal link between them)?
- Smoking cigarettes and developing lung cancer.
- Ice cream sales and drowning rates both rising in summer. (Correct answer)
- Exercising regularly and having lower blood pressure.
- Studying more hours and scoring higher on a test.
Correct answer: Ice cream sales and drowning rates both rising in summer.
Both ice cream sales and drowning rates are driven by hot weather (a third variable); neither causes the other.
Question 3: A psychologist argues: 'Children who watch violent TV shows are more aggressive.' A critic responds that aggressive children may simply prefer violent content. What logical concept does the critic's response illustrate?
- Confounding variable
- Selection bias
- Reverse causation (Correct answer)
- Overgeneralization
Correct answer: Reverse causation
Reverse causation occurs when the assumed effect (aggression) may actually be causing the assumed cause (choosing violent TV), reversing the proposed direction.
Question 4: In evaluating a proposed cause-and-effect relationship, establishing that the cause preceded the effect in time is described as which condition?
- Covariation of cause and effect
- Elimination of alternative explanations
- Temporal precedence (Correct answer)
- Dose-response relationship
Correct answer: Temporal precedence
Temporal precedence—the cause occurring before the effect—is one of the three classic criteria (along with covariation and ruling out alternatives) for establishing causation.
Question 5: A study finds a dose-response relationship: the more cigarettes smoked per day, the higher the rate of lung cancer. Why does this strengthen the causal argument?
- It proves that no other variable could cause lung cancer.
- It shows that increases in the proposed cause are associated with proportional increases in the effect, consistent with a mechanism. (Correct answer)
- It confirms that every smoker will eventually develop lung cancer.
- It eliminates the possibility that genetics influence cancer risk.
Correct answer: It shows that increases in the proposed cause are associated with proportional increases in the effect, consistent with a mechanism.
A dose-response relationship is strong evidence for causation because it shows the effect scales with the cause in a systematic, mechanistically plausible way.
Question 6: A public health researcher wants to determine whether a new vaccine causes a rare side effect. Which study design provides the strongest causal evidence?
- A case study of one patient who developed the side effect after vaccination.
- A survey asking vaccinated patients whether they experienced the side effect.
- A randomized controlled trial assigning participants to vaccine or placebo groups and monitoring side effects. (Correct answer)
- A review of news reports about the side effect following vaccine rollout.
Correct answer: A randomized controlled trial assigning participants to vaccine or placebo groups and monitoring side effects.
Randomized controlled trials minimize confounding and establish temporal precedence, making them the gold standard for causal inference.
Question 7: A manager notices that teams with standing desks submit more creative project proposals. She plans to buy standing desks for all teams to boost creativity. Which critical thinking error does this plan risk committing?
- Treating correlation as sufficient evidence of causation without investigating alternative explanations. (Correct answer)
- Failing to consider the financial cost of standing desks.
- Ignoring the fact that some employees may prefer sitting.
- Assuming creativity can be measured objectively.
Correct answer: Treating correlation as sufficient evidence of causation without investigating alternative explanations.
The manager is acting on a correlation (standing desks and creativity co-occur) without establishing that desks cause creativity—more creative teams may simply have been given desks as a perk.
Watson-Glaser Critical Thinking Appraisal Evaluating Causal Relationships 5
A company introduces mandatory ergonomic chairs and reports a 25% drop in employee sick days the following quarter.
The CEO attributes this to the chairs.
What additional information is MOST critical before accepting this causal claim?