An accounting boundary is the formal scope used to decide what is included in a measurement. In cyber security and compliance, it defines which systems, services, sensors, logs, facilities, or time periods count when calculating a result such as energy use, emissions, availability, or incident impact. The boundary matters because the same environment can produce very different numbers depending on whether you measure only the application, the full cluster, or the hosting data center.
Security teams care about accounting boundaries because they shape trust in reported data. If the boundary is vague, an attacker or careless operator can hide activity outside the measurement scope, skew telemetry, or make audits non-reproducible. Defenders use clear boundaries to separate production from test systems, track which assets feed compliance reports, and version the rules behind calculations. In practice, strong boundaries make metrics harder to game and easier to verify.