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Ref. No. [UMCES] CBL 2015-009
ACT VS15-02
44
Data Quality Assessment -
A Data Quality Assessment (DQA) is a scientific and
statistical evaluation of validated data to determine if the data are of the right type, quality, and
quantity to support their intended use. Data review is conducted to ensure that only sound data
that are of known and documented quality and meet ACT technology verification quality
objectives are used in making decisions about technology performance. Two steps were
followed to determine the validity of the analytical data – data verification and validation.
Data verification evaluates the completeness, correctness, and consistency of the test data
sets against the requirements specified in the Test Protocols. For the pH sensor verification, this
step verified that:
•
The raw data records were complete, understandable, well-labeled, and traceable;
•
All data identified in the Test Protocols were collected;
•
Instrument calibration and QC criteria were achieved;
•
Data calculations were accurate.
Data validation established:
•
Required sampling methods were used;
•
Sampling procedures and field measurements met performance criteria;
•
Required analytical methods were used;
•
QC measures were obtained and criteria were achieved.
The DQA determined that ACT’s data quality objectives were achieved. The DQA
supports conclusions that:
•
The sampling design performed very well and was very robust with respect to
changing conditions.
•
Sufficient samples were taken to enable the reviewer to see an effect if it were
present.
•
Data on the performance of the pH sensors are unambiguous, and the vendors and
buyers can make informed choices about the performance of a sensor with a high
level of certainty.
REFERENCES
American National Standards Institute and American Society for Quality Control (ANSI/ASQC).
2004. Quality Systems for Environmental Data Collection and Environmental Technology
Programs: Requirements with Guidance for Use. E4-2004. Milwaukee, WI.
Culberson, C.H. 1981. Direct potentiometry, in: Whitfield, M., and Jagner, D. (Eds.), Marine
Electrochemistry: a Practical Introduction. Wiley, pp. 187–261.
Dickson, A.G., Sabine, C.L. and Christian, J.R. (Eds.) 2007. Guide to Best Practices for Ocean
CO2 Measurements. PICES Special Publication 3:191.
Easley R.A. and Byrne, R.H. 2012. Spectrophotometric calibration of pH electrodes in seawater
using purified m-cresol purple. Environmental Science and Technology 46:5018-5024.