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| Grant
Paul, Quest Analytical, Inc |
December
2000 |
Authors Note: This article is intended to provide a wide-scope
overview of the concepts of data validation for all who utilize
analytical laboratory data. The author has significant experience
providing third-party data validation services. The article was
intended to be beneficial for those who have utilized data validation
as well as for those who are unfamiliar with data validation.
What is Data Validation?
Data Validation is a higher-level scientific-based process that
determines the technical usability of the analytical data. In
the scientific context, the term "data validation" is commonly
used when referring to a process during which a body of data is
subjected to a comparison with a set of acceptance criteria. The
acceptance criteria are designed in a manner that will enable
the data user to know if the set of data will meet the intended
purpose.
Data Validation generally can be defined to mean: A systematic
process that compares a body of data to the requirements in
a set of documented acceptance criteria.
Who Uses the Data Validation Process?
Governmental and regulatory bodies have frequently used a formal
process of data validation with environmental protection responsibility.
Many governmental projects that involve environmental cleanup,
air and water quality monitoring, and risk assessment are required
to utilize the data validation process.
Other users of the data validation process are those who rely
on analytical data to provide a reliable basis for decision making,
monitoring of manufacturing processes, research, and other non-regulatory
activities. For them, the driving force is data usability of the
data, not environmental regulatory compliance. The usability of
the data can be determined by objectively reviewing the analytical
data and associated analytical laboratory documentation and comparing
it to the data quality objectives and requirements. Thus, by knowing
the degree and extent of the usability of the data, the data can
serve its intended purpose.
Who Performs Data Validation?
Data validation can be performed by several different entities.
Commonly, the analytical laboratory providing the analytical data
may do a limited scope data validation. The laboratory's role
is generally limited to assigning data qualifiers based on events
relating to the analysis of the samples and the requirements in
the methods and procedures that were utilized by the laboratory.
In addition, the laboratory may follow other applicable contract
requirements for data reporting and reporting.
Validation of data by a party independent of the laboratory is
most often the more desirable option. A full scope data validation
process performed by such a third party for the data user ensures
an unbiased and technically sound outcome.
The ultimate data user also can undertake the data validation
process.
What are the Benefits of Data That Have Been Validated?
Data that have undergone the data validation process will subsequently
have a known degree of compliance to the applicable quality acceptance
criteria. Data qualifiers (usually coded footnotes) will have
been assigned, when appropriate, and the usability of the data
can be determined. This will benefit the regulators, decision
makers, and all who depend on data of known quality.
What is Data Verification and How Does it Differ From Data Validation?
The US Environmental Protection Agency (EPA) also uses a process
called Data Verification that complements the Data Validation
process. Data Verification focuses on the aspects relevant to
sample collection criteria that are specified in a standard or
contract. This is a systematic and mechanical determination of
whether the samples were collected and handled in accordance with
contractual requirements. If Data Verification is done, it is
performed before Data Validation.
What is Data Assessment?
This process is makes use of statistical tools and principles
to determine if data meet the documented requirements of their
intended use. Statistical tests that identify data outliers, distributions,
and biases are employed during Data Assessment to objectively
determine the conformance to the requirements.
Summary
Data Verification, Data Validation, and Data Assessment are related
processes that are used to measure, monitor, and document the
degree of compliance to stated quality requirements of analytical
data. While all three processes require technical competence,
Data Validation requires extensive laboratory systems knowledge
and the ability to apply consistent professional judgment during
the process.
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