1. The Correlation vs Causation Turmoil
Unit 4 – Bivariate Data
1/18/2019
Algebra 1 Institute

2. Correlation & Causation
Causation: an action or occurrence can cause another
Example: smoking causes lung cancer
Correlation: two things occur together
Example: smoking is correlated with alcoholism
If one action causes another, then they are most certainly correlated. But …
1/18/2019
Algebra 1 Institute

3. Correlation & Causation
… just because two things occur together does not mean that one caused the other, even if it seems to make sense.
1/18/2019
Algebra 1 Institute

4. Eating Breakfast and Success in School
Eating breakfast has long been correlated with success in school for elementary school children
It would be easy to conclude that eating breakfast causes students to be better learners.
However, those who don’t eat breakfast are also more likely to be absent or tardy
It is absenteeism that is playing a significant role in their poor performance.
When researchers retested the breakfast theory, they found that, independent of other factors, breakfast only helps undernourished children perform better.
1/18/2019
Algebra 1 Institute

5. Girls and Soap Operas
Girls who watch soap operas are more likely to have eating disorders
Correlation between soap opera watching and eating disorders
Causation?
“Therefore, our results suggest that if young girls watch soaps and music television often, this is related to higher restrained eating and body dissatisfaction … ”
“… we cannot say anything about causality.”
Anschutz et al. (2009). Watching your weight? The relations between watching soaps and music television and body dissatisfaction and restrained eating in young girls. Psychology and Health 24 (9)
1/18/2019
Algebra 1 Institute

6. Correlation & Causation
Correlated occurrences may be due to a common, underlying cause
Example:
Red hair is correlated with blue eyes
Stems from a common genetic specification which codes for both
1/18/2019
Algebra 1 Institute

7. Correlation & Causation
Correlation may also be observed when causality exists
Example:
It is well-established that cigarette smoking not only correlates with lung cancer, but actually causes it.
To establish cause, we would have to rule out the possibility that smokers are more likely to live in urban areas, where there is more pollution
Or any other possible explanation for the observed correlation.
1/18/2019
Algebra 1 Institute

8. We Like Explanations! In general, we should be wary of our own bias
The media often concludes a causal relationship among correlated observances when causality was not even considered by the study itself.
Without clear reasons to accept causality, we should only accept correlation.
Two events occurring in close proximity does not imply that one caused the other, even if it seems to makes perfect sense.
1/18/2019
Algebra 1 Institute

9. Videos TED talk FreakonomicVideos
The danger of mixing up causality and correlation: Ionica Smeets
FreakonomicVideos
Correlation vs Causality
1/18/2019
Algebra 1 Institute