Verification and validation are independent procedures that are used together for checking
that a product, service, or system meets requirements and specifications and that it fulfills its
intended purpose. These are critical components of a quality management system such as ISO
9000. The words "verification" and "validation" are sometimes preceded with "independent",
indicating that the verification and validation is to be performed by a disinterested third
party. "Independent verification and validation" can be abbreviated as "IV&V".
It is sometimes said that validation can be expressed by the query "Are you building the
right thing?" and verification by "Are you building the thing right?".
In practice, the usage of these terms varies. Sometimes they are even used interchangeably.
The PMBOK guide, a standard adopted by IEEE, defines them as follows in its 4th edition:
"Validation. The assurance that a product, service, or system meets the needs of the
customer and other identified stakeholders. It often involves acceptance and suitability
with external customers. Contrast with verification." "Verification. The evaluation of whether or
not a product, service, or system complies with a regulation, requirement, specification,
or imposed condition. It is often an internal process. Contrast with validation."
Overview Verification is intended to check that a product,
service, or system meets a set of design specifications. In the development phase, verification procedures
involve performing special tests to model or simulate a portion, or the entirety, of
a product, service or system, then performing a review or analysis of the modeling results.
In the post-development phase, verification procedures involve regularly repeating tests
devised specifically to ensure that the product, service, or system continues to meet the initial
design requirements, specifications, and regulations as time progresses. It is a process that is
used to evaluate whether a product, service, or system complies with regulations, specifications,
or conditions imposed at the start of a development phase. Verification can be in development,
scale-up, or production. This is often an internal process.
Validation is intended to ensure a product, service, or system result in a product, service,
or system that meets the operational needs of the user. For a new development flow or
verification flow, validation procedures may involve modeling either flow and using simulations
to predict faults or gaps that might lead to invalid or incomplete verification or development
of a product, service, or system. A set of validation requirements, specifications, and
regulations may then be used as a basis for qualifying a development flow or verification
flow for a product, service, or system. Additional validation procedures also include those that
are designed specifically to ensure that modifications made to an existing qualified development
flow or verification flow will have the effect of producing a product, service, or system
that meets the initial design requirements, specifications, and regulations; these validations
help to keep the flow qualified. It is a process of establishing evidence that provides a high
degree of assurance that a product, service, or system accomplishes its intended requirements.
This often involves acceptance of fitness for purpose with end users and other product
stakeholders. This is often an external process. It is sometimes said that validation can be
expressed by the query "Are you building the right thing?" and verification by "Are you
building it right?". "Building the right thing" refers back to the user's needs, while "building
it right" checks that the specifications are correctly implemented by the system. In some
contexts, it is required to have written requirements for both as well as formal procedures or protocols
for determining compliance. It is entirely possible that a product passes
when verified but fails when validated. This can happen when, say, a product is built as
per the specifications but the specifications themselves fail to address the user’s needs.
Activities Verification of machinery and equipment usually
consists of design qualification, installation qualification, operational qualification,
and performance qualification. DQ is usually a vendor's job. However, DQ can also be performed
by the user, by confirming through review and testing that the equipment meets the written
acquisition specification. If the relevant document or manuals of machinery/equipment
are provided by vendors, the later 3Q needs to be thoroughly performed by the users who
work in an industrial regulatory environment. Otherwise, the process of IQ, OQ and PQ is
the task of validation. The typical example of such a case could be the loss or absence
of vendor's documentation for legacy equipment or do-it-yourself assemblies and, therefore,
users should endeavour to acquire DQ document beforehand. Each template of DQ, IQ, OQ and
PQ usually can be found on the internet respectively, whereas the DIY qualifications of machinery/equipment
can be assisted either by the vendor's training course materials and tutorials, or by the
published guidance books, such as step-by-step series if the acquisition of machinery/equipment
is not bundled with on- site qualification services. This kind of the DIY approach is
also applicable to the qualifications of software, computer operating systems and a manufacturing
process. The most important and critical task as the last step of the activity is to generating
and archiving machinery/equipment qualification reports for auditing purposes, if regulatory
compliances are mandatory. Qualification of machinery/equipment is venue
dependent, in particular items that are shock sensitive and require balancing or calibration,
and re-qualification needs to be conducted once the objects are relocated. The full scales
of some equipment qualifications are even time dependent as consumables are used up
or springs stretch out, requiring recalibration, and hence re-certification is necessary when
a specified due time lapse. Re-qualification of machinery/equipment should also be conducted
when replacement of parts, or coupling with another device, or installing a new application
software and restructuring of the computer which affects especially the pre-settings,
such as on BIOS, registry, disk drive partition table, dynamically-linked libraries, or an
ini file etc., have been necessary. In such a situation, the specifications of the partssoftware
and restructuring proposals should be appended to the qualification document whether the
partssoftware are genuine or not. Torres and Hyman have discussed the suitability of non
genuine parts for clinical use and provided guidelines for equipment users to select appropriate
substitutes which are capable to avoid adverse effects. In the case when genuine partssoftware
are demanded by some of regulatory requirements, then re-qualification does not need to be
conducted on the non genuine assemblies. Instead, the asset has to be recycled for non regulatory
purposes. When machinery/equipment qualification is
conducted by a standard endorsed third party such as by an ISO standard accredited company
for a particular division, the process is called certification. Currently, the coverage
of ISO/IEC 15408 certification by an ISO/IEC 27001 accredited organization is limited,
the scheme requires a fair amount of efforts to get popularized.
Categories of validation Validation work can generally be categorized
by the following functions: Prospective validation – the missions conducted
before new items are released to make sure the characteristics of the interests which
are functioning properly and which meet safety standards. Some examples could be legislative
rules, guidelines or proposals, methods, theoriesmodels products and services
Retrospective validation – a process for items that are already in use and distribution
or production. The validation is performed against the written specifications or predetermined
expectations, based upon their historical data/evidences that are documented/recorded.
If any critical data is missing, then the work can not be processed or can only be completed
partially. The tasks are considered necessary if:
prospective validation is missing, inadequate or flawed.
the change of legislative regulations or standards affects the compliance of the items being
released to the public or market. reviving of out-of-use items.
Some of the examples could be validation of: ancient scriptures that remain controversial
clinical decision rules data systems
Full-scale validation Partial validation – often used for research
and pilot studies if time is constrained. The most important and significant effects
are tested. From an analytical chemistry perspective, those effects are selectivity, accuracy, repeatability,
linearity and its range. Cross-validation
Re-validation/Locational or Periodical validation – carried out, for the item of interest
that is dismissed, repaired, integrated/coupled, relocated, or after a specified time lapse.
Examples of this category could be relicencing/renewing driver's license, recertifying an analytical
balance that has been expired or relocated, and even revalidating professionals. Re-validation
may also be conducted when/where a change occurs during the courses of activities, such
as scientific researches or phases of clinical trial transitions. Examples of these changes
could be sample matrices
production scales population profiles and sizes
out-of-specification] investigations, due to the contamination of testing reagents,
glasswares, the aging of equipment/devices, or the depreciation of associated assets etc.
In GLP accredited laboratories, verification/revalidation will even be conducted very often against
the monographs of the Ph.Eur., IP to cater for multinational needs or USP and BP etc
to cater for national needs. These laboratories must have method validation as well.
Concurrent validation – conducted during a routine processing of services, manufacturing
or engineering etc. Examples of these could be
duplicated sample analysis for a chemical assay
triplicated sample analysis for trace impurities at the marginalized levels of detection limit,
or/and quantification limit single sample analysis for a chemical assay
by a skilled operator with multiplicated online system suitability testings
Aspects of validation The most tested attributes in validation tasks
may include, but are not limited to Selectivity/specificity
Accuracy and precision Repeatability
Reproducibility Limit of detection – especially for trace
elements Limit of quantification
Curve fitting and its range System suitability – In a broad way, it
usually includes a test of ruggedness among inter-collaborators, or a test of robustness
within an organization However, the U.S. Food and Drug Administration has specifically defined
it for its administration, as "System suitability testing is an integral part of many analytical
procedures. The tests are based on the concept that the equipment, electronics, analytical
operations and samples to be analyzed constitute an integral system that can be evaluated as
such. System suitability test parameters to be established for a particular procedure
depend on the type of procedure being validated". In some cases of analytical chemistry, a system
suitability test could be rather a method specific than universal. Such examples are
chromatographic analysis, which is usually media sensitive However to the date of this
writing, this kind of approaches are limited to some of pharmaceutical compendial methods,
by which the detecting of impurities, or the quality of the intest analyzed are critical.
This is probably largely due to
their intensive labouring demands and time consumption
their confinements by the definition of the term defined by different standards.
To solve this kind of difficulties, some regulatory bodies or compendial methods usually provide
the advices on what the circumstances or conditions that the performing of a specified system
suitability test should be beared and compulsory. Industry references
These terms generally apply broadly across industries and institutions. In addition,
they may have very specific meanings and requirements for specific products, regulations, and industries.
Some examples: Software and computer systems
Food and Drug Pharmaceuticals The design, production, and
distribution of drugs are highly regulated. This includes software systems. For example
in the USA, the Food and Drug Administration have regulations in Part 21 of the Code of
Federal Regulations. Nash et al. have published a book which provides a comprehensive coverage
on the various validation topics of pharmaceutical manufacturing processes. Some companies are
taking a risk-based approach to validating their GAMP system if one understands the regulatory
requirements very well while the most of others follows the conventional process It is a part
of GxP management. The aspects of validation and verification are even more intense and
emphasized if an OOS occurs. Very often under this circumstance, a multiplicated sample
analysis is required for conducting the OOS investigation in a testing laboratory.
Medical devices The FDA has validation and verification requirements for medical devices.
See guidance: and ISO 13485 Manufacturing process and cleaning validation
are compulsory and regulated by the U.S. Food and Drug Administration
Food hygiene: example Clinical laboratory medicine: ISO 15198:2004
Clinical laboratory medicine—In vitro diagnostic medical devices—Validation of user quality
control procedures by the manufacturer
Health care: example Greenhouse gas: ISO 14064 ANSI/ISO: Greenhouse
gases — Requirements for greenhouse gas validation and verification bodies for use
in accreditation or other forms of recognition Traffic and transport
Road safety audit Periodic motor vehicle inspection
Aircraft noise: example Aircraft:[2]
Model:[3] (Ni-Cd) cells: example
ICT Industry: example Civil engineering
Buildings – Roads –
Bridges –
Economics Accounting
Agriculture – applications vary from verifying agricultural methodology and production processes
to validating agricultural modeling Real estate appraisal – audit reporting
and authentication See also
Accreditation Change control
Certification of voting machines Comparability
Cross-validation Formal verification
Integrity Testing ISO 17025
System testing Systematic political science
Usability testing Functional verification
Verification and Validation Verification and Validation of Computer Simulation
Models Further reading
Majcen, N.; Taylor, P.. Practical examples on traceability, measurement uncertainty and
validation in chemistry 1. European Union. p. 217.
External links Maturity of verification and validation in
ICT companies Organisational maturity and functional performance
Notes and references