Accuracy is the measure of agreement between an analytical result and its true or accepted value. Deviations from a standard value represent a change in the measurement system. Sampling accuracy is assessed by collecting and analyzing field and trip blanks for the parameters of interest. Analytical accuracy is determined by comparing results from the analysis of matrix spikes, surrogates, or check standards to their known values. Data precision is the determination of measurements under a given set of conditions, or a quantitative measure of the variability of a group of measurements compared to their average value.
Precision is measured by analyzing duplicate samples.
Traceability is the extent to which reported analytical results can be substantiated by supporting documentation.