Correlation vs Causation Statistics Example 3
Follow the full solution, then compare it with the other examples linked below.
Example 3
mediumData shows that countries with higher chocolate consumption per capita have more Nobel Prize winners. A blogger writes: 'Eating chocolate makes you smarter!' Give two reasons why this conclusion is flawed.
Solution
- 1 Step 1: Reason 1 — Confounding variable: wealthier countries can afford more chocolate AND invest more in education and research, leading to more Nobel Prizes. Wealth is the lurking variable.
- 2 Step 2: Reason 2 — Ecological fallacy: the data compares countries, not individuals. Even if the country-level pattern exists, it does not mean any individual who eats more chocolate will become smarter.
Answer
The conclusion is flawed because (1) national wealth is a confounding variable that drives both chocolate consumption and Nobel Prizes, and (2) country-level data cannot be applied to individual behaviour (ecological fallacy).
This famous example illustrates how correlations at the aggregate level can be misleading. Confounding variables and ecological fallacies are two common reasons why observed correlations do not imply causal relationships between variables.
About Correlation vs Causation
Correlation shows that two variables move together in some pattern; causation means one variable actually makes the other change. Observing a correlation does not prove causation because a hidden third variable (confounder) may be driving both.
Learn more about Correlation vs Causation →More Correlation vs Causation Examples
Example 1 easy
A study finds that towns with more ice-cream shops tend to have higher crime rates. Does this mean i
Example 2 mediumA newspaper headline reads: 'Students who sleep more get higher grades — sleeping longer causes bett
Example 4 hardA pharmaceutical company observes that patients who take their new supplement have lower rates of he