What is the purpose of an error budget during calibration?

• A. A budget for calibration equipment
• B. A plan listing allowable error sources and their contributions; used to ensure the total measurement uncertainty is within spec
• C. A list of calibration steps
• D. A schedule for maintenance

Answer: (B)

The main idea is to plan and quantify how much each potential error source can contribute to the final measurement so that the total uncertainty stays within the required spec. In calibration, you identify all the factors that can affect a measurement—like instrument resolution, drift, environmental conditions, repeatability, and the uncertainty of the reference standard—and assign a maximum allowable contribution to each. By combining these contributions—often using a root-sum-square method for independent errors—you see whether the overall estimated uncertainty meets the specification. This makes it possible to target the biggest sources of error and decide where improvements or additional calibration steps are needed to keep measurements within tolerance. It isn’t about budgeting equipment, listing steps, or scheduling maintenance, which are logistical aspects rather than uncertainty planning.