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Randomization

As explained in Causal AI

Random assignment, or randomization, allocates units or intervention values to conditions according to a random mechanism.

Randomization assigns units or intervention values through a random mechanism. In causal analysis, random assignment is a stochastic intervention: a platform digitally flips a coin to set the target variable. section 7.5.1

Randomization removes incoming causal influence from unknown common causes. It can therefore protect an experiment when the assumed causal DAG is incomplete, even though an ideal intervention may already identify the effect under a correct DAG. section 7.5.1 section 7.7

Implementation has two layers:

  • Choose outcomes according to a specified distribution; computers emulate this process with deterministic pseudorandom number generators initialized by a random seed. section 2.2.2
  • Assign experimental units to conditions independently of causes that might otherwise affect both treatment and outcome. section 7.5.1

Online gaming experiment

A digital experimentation platform randomly assigns players to high- or low-engagement groups, then compares in-game purchases. Assigning the first players to one group and later players to another could fail if login time affects both engagement and purchases. section 7.5.1

Figure 7.12 Randomization eliminates incoming edges from unknown common causes.
figure

Diagram showing how randomization eliminates incoming edges from unknown common causes. section 7.5.1

How Causal AI covers it

How deep it goes
Explains stochastic intervention, contrasts it with ideal intervention, and traces protection against unknown causes; implementation reaches pseudorandom sampling.
Examples
Uses a digital gaming experiment, player engagement groups, login timing, and pgmpy and Pyro sampling examples.
What it assumes
Assumes causal interventions and DAGs, while defining random generation and pseudorandom mechanisms explicitly.
What you can do after
Apply it via a randomized experimentation platform or seeded pseudorandom generator to assign intervention values.
How it connects
Connects stochastic intervention with causal DAGs, graph surgery, intervention operators, and unknown common causes.

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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.