Causal Tracing

Causal tracing (causal mediation analysis) identifies which intermediate computations causally mediate the relationship between inputs and outputs. It reveals not just what correlates with behavior, but what causes it.

Core Concepts

Three Types of Causal Effects

1. Total Effect: Change in output when modifying input
2. Direct Effect: Effect of restoring a component from clean to corrupted run
3. Indirect Effect: Effect of corrupting a component in an otherwise clean run

The Interchange Intervention

Swap activations between two runs to test causal relationships:

• Source run: Produces the activation value
• Base run: Receives the swapped activation