IDEA FOUND // IDEA 137
Potential Outcomes
“An individual causal effect compares two futures, but only one can be observed.”
01 / PLAINLY
What it means, plainly
The potential-outcomes framework imagines one outcome for a unit with treatment and another without it. We observe only one; the other is the counterfactual, meaning the unseen alternative outcome.
02 / CONTEXT
A little more
The framework defines an outcome for each unit under treatment and another under control. Their difference is the individual effect, but the unseen counterfactual creates the fundamental causal-inference problem.
03 / WHY IT MATTERS
Why it matters
It clarifies which comparison defines a causal effect and why observing one person's change is not enough.
04 / EXAMPLE
A familiar example
For one student we observe the grade with tutoring or without it, never both in the same period under identical conditions.
05 / LIMIT
What it does not mean
Data do not reveal an individual counterfactual without design and assumptions; average effects need not describe every person.
06 / NOTICE
Notice it in your day
For one student and a tutoring program, write the two potential outcomes. Circle the only one observable in a single period and label the other counterfactual.
FINAL NOTE
The idea worth keeping
State precisely which alternative outcome provides the comparison.
QUESTIONS / 02
Questions people still have
What is a counterfactual outcome?
The alternative result that would have occurred under the unobserved condition.
Why can we not see a complete individual effect?
The same unit cannot be observed under treatment and control at once in identical conditions.