How do accuracy and precision differ in analytical testing?

Why

Imagine five assay results near 85 percent when the known reference concentration corresponds to 100 percent. If those results barely vary, precision may be high but accuracy poor. Assess accuracy using suitable reference materials or recovery designs and precision across relevant repeatability and intermediate precision conditions.

Performance must be defined for the intended analytical use and concentration range rather than inferred from one calibration point. Matrix effects, sample preparation, equipment and analysts can affect bias and variability differently. For some qualitative methods, different performance characteristics may be appropriate, so avoid applying a quantitative validation checklist mechanically.

Report uncertainty and accepted criteria before interpreting results. A small standard deviation does not, by itself, demonstrate method suitability for a release decision.