LABCRUX GUIDE

Measurement uncertainty in lab reports

State what the uncertainty represents, how it was obtained, and how it propagates into derived quantities.

Name the uncertainty

A number after ± is ambiguous without context. State whether it is instrument resolution, standard deviation, standard error, confidence interval, or a combined standard uncertainty.

Match units and precision

Absolute uncertainty carries the same unit as the quantity. Report the value to a precision consistent with the uncertainty and retain fuller precision in the calculation record.

Propagate with assumptions visible

Root-sum-square rules generally assume independent inputs and linearized behavior. Correlation or nonlinear models require a more complete method.

Keep uncertainty distinct from disagreement

Measurement uncertainty describes dispersion or knowledge about a value; percent error compares an observation with a reference. Neither automatically establishes method validity.

Sources and boundaries

  1. [1]

    JCGM measurement uncertainty publications

  2. [2]

    NIST/SEMATECH e-Handbook of Statistical Methods

Solice develops LabCrux. The independent sources above do not sponsor or endorse the product. This page explains a review method; your experimental evidence, course instructions, and instructor remain authoritative.