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Factual condition

As explained in Causal AI

A factual condition is an observed fact, event, or piece of evidence that restricts the population or scope described by a conditional query.

A factual condition is an observed fact, event, or piece of evidence that narrows the population under discussion. In P(Y | X = x), the factual condition appears after the vertical bar and filters attention to cases where X actually equals x. section 8.2.2

Keep factual conditions distinct from hypothetical conditions:

  • A factual query asks what Y is for cases where X = x: P(Y | X = x). section 8.2.3
  • A hypothetical query asks what Y would be if X were set to x, regardless of its observed causes. section 8.2.3
  • The two can combine: ask a hypothetical question about a population already filtered by a factual condition. section 8.2.3

Game-player example

“What would in-game purchases be for players with high side-quest engagement?” uses high engagement as a factual condition. A counterfactual instead asks what purchases would be if engagement were high for a player whose observed engagement was low; the low engagement remains the factual condition. section 8.2.2 section 8.2.4

Factual and hypothetical conditions may conflict, producing a counterfactual query. When they agree, the consistency rule removes the redundant hypothetical condition: P(YX=x | X=x, Z=z) = P(Y | X=x, Z=z). section 8.2.4 section 8.2.5

Figure 8.4 Elements of a conditional counterfactual hypothetical formalized in counterfactual notation
figure

Use the notation diagram to locate factual conditions and distinguish them from hypothetical conditions in conditional counterfactual queries. section 8.2.4

How Causal AI covers it

How deep it goes
Defines the notation, contrasts factual and hypothetical conditions, and applies consistency but does not develop estimation procedures.
Examples
Uses player engagement and in-game purchases to contrast population filtering, intervention questions, and conflicting observed outcomes.
What it assumes
Assumes conditional probability notation and develops the distinction between observed filtering and hypothetical intervention.
What you can do after
Evaluate/understand whether a query describes observed subpopulations, hypothetical interventions, or counterfactual conflicts.
How it connects
Connects factual conditions to conditional probability, conditional hypotheticals, interventions, counterfactuals, and the consistency rule.

Related concepts

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