Causation Math Example 3

Follow the full solution, then compare it with the other examples linked below.

Example 3

easy
Countries with more TV sets per capita have higher life expectancy. Does this mean buying TVs causes longer lives? Identify the likely confounding variable.

Solution

  1. 1
    The claim is implausible — TVs don't cause longer lives
  2. 2
    Confounding variable: wealth/GDP — richer countries can afford both more TVs AND better healthcare
  3. 3
    Wealth → TVs AND wealth → better healthcare → longer life expectancy

Answer

Confounding variable is national wealth. TVs and longevity are both caused by higher GDP, not by each other.
Many global correlations are explained by wealth as a confounder. Richer nations have more of almost everything. Always ask 'What else could explain both variables?' before concluding causation.

About Causation

Causation exists when one variable directly produces or influences a change in another variable — distinct from mere correlation or association.

Learn more about Causation →

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