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Table D. Data Quality Objectives and Criteria for Microbial Samples
Data Quality
Indicator
Evaluation Process
Performance Measure
MERC DQO
Precision
Analyze at least 10 % of samples
in duplicate.
Relative Percent
Difference (RPD).
< 20 % average RPD.
Bias
Experiment Bias:
Ensure proper
calibration/verification and
maintenance of
equipment/analytical
instrumentation; ensure proper
sample handling to avoid
contamination.
N/A
N/A
Operator Bias:
Ensure a second,
suitably-qualified operator counts
at least 10 % of samples.
Relative Percent
Difference (RPD).
< 20 % average RPD.
Representativeness Ensure sample water contains
biota representative of harbor
water in terms of species
composition and richness. Ensure
pre-treatment/control and post-
treatment/treatment samples are
handled and analyzed in the same
manner.
N/A – Qualitative term.
N/A – Qualitative term.
Comparability
Routine procedures are conducted
according to appropriate SOPs to
ensure consistency between tests.
Ensure correct implementation of
SOPs.
N/A – Qualitative term.
N/A – Qualitative term.
Completeness
Calculate percentage of valid
samples analyzed out of the total
number of samples collected.
Percent Completeness
(%C)
Greater than 90 %C.
Sensitivity
Limit of detection (LOD) is
determined for each analysis type,
and reported in the product
literature.
Limit of Detection (LOD) Determined by the
manufacturer, dependent
on the sample volume
analyzed.