Correlation vs Causation Flashcards
Terminology : “Individuals” (study subjects, participants, units)
Ex: European Adults
Terminology : “treatment”
Ex: Chocolate consumption
Terminology : “outcome”
Ex: Heart disease
Correlation Definition
Correlation is a technical term, which implies a relationship or link
“Among those in the top-tier of chocolate consumption, 12 percent
developed or died of cardiovascular disease during the study, compared to
17.4 percent of those who didn’t eat chocolate.”
Is there any correlation(relationship) between chocolate consumption and heart disease?
Yes, this points to an association (correlation).
Causation Definition
Causation is the technical term that implies the existence of a factor directly leads to an outcome
“Among those in the top-tier of chocolate consumption, 12 percent
developed or died of cardiovascular disease during the study, compared to
17.4 percent of those who didn’t eat chocolate.”
Does chocolate consumption lead to an increase in heart disease?
This study doesn’t prove a cause-and-effect relationship between chocolate and reduced risk of heart disease and stroke.
What is the Golden Rule of Establishing Causality?
If the treatment and control groups are similar, except for the treatment, then the differences between the outcomes in the two groups can be ascribed to the treatment.
Confounding Variables
If the treatment and control groups have systematic differences besides the treatment, then it might be difficult to prove causality
Such differences are often present in observational studies
When they lead researchers astray, they are called confounding variables.
What is a Randomized Controlled Experiment?
If you assign individuals to treatment and control at random, the two groups are likely to be similar except for the treatment.
You can mathematically account for variability in the assignment.
