How can you quantify liquid-handler accuracy and precision?

Why

For a nominal 10 µL transfer, collect repeated measurements across channels, plate positions and operating runs. A suitable gravimetric or photometric method can estimate delivered volume, provided density, evaporation, calibration and method limits are controlled. Calculate mean measured volume, bias as measured minus target, relative bias in percent, standard deviation and coefficient of variation.

The word accuracy is often used broadly, but trueness captures systematic closeness to target while precision measures spread. Distinguish repeatability from variability across days or operators. ISO 23783 provides the relevant terminology, procedures and reporting concepts for automated liquid handlers.

An example with a mean of 9.7 µL and a CV of 0.5% is very precise but biased low. Acceptance limits must reflect intended assay tolerance, not be invented from a universal percentage.