Equation 19 · How Mechanistic Interpretability Research Is Actually Done
What does this equation mean?
Read the formula alongside the article passage below. Each part has a deeper page with its role in the equation, the supporting passage and nearby citations.
This mathematical expression combines the displayed quantities; its precise role follows from the surrounding article text. Read the equation part by part below; each part has a contextual explanation and a link to its mathematical background.
Read it piece by piece
Symbol m
m is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
How to interpret it
Read this expression with the definitions, units, and assumptions supplied by the article.
What the article says around this equation
The standard instrument is activation patching. Run the model once on a clean input and once on a deliberately corrupted variant of it — a single token changed, a name swapped — caching every intermediate activation from both runs. Then run the model a third time on the corrupted input, but with one chosen component’s activation overwritten by the value it took during the clean run, and measure the resulting change in some scalar behavioural metric m , typically the gap between the correct answer’s logit and a specific incorrect competitor’s logit:
Sources cited in the article section
- [11] Towards Best Practices of Activation Patching in Language Models: Metrics and Methods ↗
- [12] Localizing Model Behavior with Path Patching ↗
- [14] Towards Automated Circuit Discovery for Mechanistic Interpretability ↗
- [13] Locating and Editing Factual Associations in GPT ↗
These citations give research context. Read each source to check which claims it supports.
Return to How Mechanistic Interpretability Research Is Actually Done