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Factual outcome

As explained in Causal Inference for Data Science

A factual outcome is the outcome actually observed for a unit under the treatment or condition it received.

A factual outcome is the response actually observed after a unit receives, or does not receive, a treatment. For patient i, Y(i) is observable, while Y₀(i) and Y₁(i) describe outcomes under both possible assignments and only one is seen. If T(i)=1, Y(i)=Y₁(i); otherwise, Y(i)=Y₀(i). section 10.1.1

The factual outcome anchors causal comparisons: the unobserved result under the alternative assignment is the counterfactual outcome. In time-based designs, the observed series follows the untreated potential outcome before the event and the treated potential outcome afterward. section 10.1.1 section 11.2.2

Patient recovery table

Holden receives treatment and recovers, so T(i)=1 and Y(i)=1; the factual outcome is recovery, while the untreated potential outcome remains unavailable in ordinary observed data. Table 10.1 compares this pattern with patients who do not recover or receive no treatment. section 10.1.1

Table 10.1 Hypothetical example of POs with assignment (T(i)) and observed recovery (Y(i))
Name
i
Y 0( i)
Y 1( i)
T( i)
Y( i)
Drummer
1
0
0
1
0
Burton
2
1
0
1
0
Holden
3
0
1
1
1
Avasarala
4
1
1
0
1

Compare treatment assignment, both potential outcomes, and the single factual outcome observed for each patient. section 10.1.1

How Causal Inference for Data Science covers it

How deep it goes
Defines the observed outcome, relates it to treatment assignment, and illustrates it with patient and time-based examples.
Examples
Uses a hypothetical patient-recovery table and a time-event process to distinguish observed outcomes from unobserved alternatives.
What it assumes
Assumes treatment assignment and outcome notation while introducing the distinction between observed, potential, and counterfactual outcomes.
What you can do after
Evaluate causal effects by comparing factual outcomes with modeled outcomes under an alternative treatment decision.
How it connects
Connects factual outcomes to potential outcomes, counterfactual outcomes, treatment assignment, and causal effect estimation.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Causal Inference for Data Science. The section links point to the parts of the book it draws on.