uncertainty budget

**Uncertainty Budget** is a **structured tabular analysis listing all sources of measurement uncertainty, their magnitudes, types, distributions, and contributions to the combined uncertainty** — the systematic documentation of every error source in a measurement process, organized to calculate the total uncertainty. **Uncertainty Budget Structure** - **Source**: Description of each uncertainty contributor (repeatability, calibration, temperature, resolution, etc.). - **Type**: A (statistical) or B (other means) — classification per GUM. - **Distribution**: Normal, rectangular, triangular, or other — determines divisor for standard uncertainty. - **Standard Uncertainty**: Each source converted to a standard uncertainty ($u_i$) in the same units. - **Sensitivity Coefficient**: How much the measurement result changes per unit change in each source ($c_i$). **Why It Matters** - **Transparency**: The budget makes all assumptions explicit — reviewable and auditable. - **Improvement**: Identifies the dominant uncertainty contributors — focus improvement on the largest sources. - **ISO 17025**: Accredited laboratories must maintain uncertainty budgets for all reported measurements. **Uncertainty Budget** is **the blueprint of measurement doubt** — a comprehensive accounting of every uncertainty source for transparent, traceable, and improvable measurement results.