ABSTRACT
In analytical work, quality can be defined as the ‘‘delivery of reliable information within an
agreed span of time, under agreed conditions, at agreed costs, and with the necessary
aftercare’’ (FAO 1998). The agreed conditions include specifications as to data quality
objectives (DQOs), which include precision, accuracy, representativeness, completeness,
and comparability. These objectives are directly related to ‘‘fitness of use’’ of the data and
they determine the degree of total variability (uncertainty or error) that can be tolerated in the
data. The DQOs ultimately determine the necessary quality control (QC).
