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CONCEPT Cited by 1 source

Time to test theories

Definition

Time to Test Theories (TTTT) is the elapsed time from an engineer proposing a hypothesis (e.g., "did this deploy cause it?", "is it a feature flag?", "is it a dependency regression?") to receiving evidence-backed validation or refutation. Measured for engineer-initiated follow-up investigations, not auto-triggered triages.

Instacart's Blueberry achieves ~3 minutes average TTTT across ~7,000 engineer-initiated theory checks per month.

Design principle

"Historical priors should inform the investigation, but live evidence should decide it." — The system compares historical context with live operational data, then narrows: inspect a suspicious PR, review a flag change, look at a dependency edge, or go deeper into a trace. (Source: sources/2026-07-14-instacart-blueberry-on-call-reasoning-harness)

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