Evaluating Causal Relationships Flashcards
7 cards from real Watson-Glaser Critical Thinking Appraisal practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Evaluating Causal Relationships flashcards as text
A city installs more streetlights in high-crime neighborhoods, and crime drops by 20% over the next year. A resident concludes that the streetlights caused the crime reduction. Which alternative explanation most weakens this causal claim?
Answer: The city also increased police patrols in those neighborhoods during the same period.
A concurrent intervention (increased patrols) is a confounding variable that could independently explain the crime reduction, undermining the streetlight-as-cause claim.
Which of the following best describes the logical fallacy 'post hoc ergo propter hoc'?
Answer: Assuming that because one event followed another, the first caused the second.
'Post hoc ergo propter hoc' means 'after this, therefore because of this'—incorrectly inferring causation from temporal sequence alone.
Researchers find that people who eat breakfast regularly have higher academic performance. A school mandates breakfast for all students. Which assumption is necessary for this policy to achieve its goal?
Answer: The correlation between breakfast and performance reflects a causal relationship.
The policy only works if eating breakfast actually causes better performance, not merely if it correlates with it (e.g., via a third factor like household stability).
A study shows that hospitals with more nurses per patient have lower patient mortality rates. An administrator concludes: 'Hiring more nurses will reduce deaths.' What is the strongest challenge to this conclusion?
Answer: Better-funded hospitals may both hire more nurses and have other quality advantages that reduce mortality.
Reverse causation or a shared underlying cause (hospital funding/quality) could explain the correlation without nurse staffing being the direct cause.
In Watson-Glaser reasoning, which of the following scenarios demonstrates a 'necessary cause' rather than a 'sufficient cause'?
Answer: Oxygen must be present for a fire to burn, but oxygen alone does not start a fire.
A necessary cause must be present for the effect to occur but does not guarantee it; oxygen is required for fire but alone cannot produce it.
Teen smartphone ownership increased dramatically at the same time teen anxiety rates rose. A commentator declares smartphones are causing teen anxiety. Which evidence would most SUPPORT (rather than undermine) this causal claim?
Answer: An experiment in which randomly selected teens who reduced screen time showed measurable anxiety decreases compared to a control group.
A randomized controlled experiment that manipulates the proposed cause and observes the effect provides the strongest evidence for causation.
A farmer notices that fields treated with a new fertilizer yield 30% more crops. He concludes the fertilizer caused the increase. Which factor would most threaten this conclusion if true?
Answer: The treated fields happened to receive significantly more rainfall than the untreated fields that year.
If treated and untreated fields had different rainfall, rainfall—not the fertilizer—could be the true cause of the yield difference.