A risk register is a structured log of identified project risks. Each entry typically includes: risk description, category (technical, schedule, financial, regulatory, weather, etc.), likelihood (low/medium/high or 1-5 scale), impact (cost or schedule magnitude), risk score (likelihood times impact), owner, mitigation plan, contingency reserve, and status. The register is reviewed at recurring project meetings; new risks get added, existing risks get re-scored, and closed risks get archived.
Risk registers shift from theoretical to actionable when they drive contingency budgeting and trigger pre-defined responses. A risk scored at 30% likelihood with $200K cost impact carries an expected value of $60K, which justifies $60K of contingency reserve. When the trigger fires (the risk becomes near-certain), the pre-planned mitigation kicks in immediately rather than the team having to invent a response under pressure. On small commercial projects the risk register is often informal; on larger projects it is a contract deliverable.