verification and validation

Software verification and validation

Software testing is used in association with verification and validation:^[16]

• Verification: Have we built the software right (i.e., does it match the specification?)? It is process based.
• Validation: Have we built the right software (i.e., is this what the customer wants?)? It is product based
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Verification is a Quality control process that is used to evaluate whether or not 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 Quality assurance 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.

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?" "Building the right thing" refers back to the user's needs, while "building it right" checks that the specifications be 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.

Activities

Verification of machinery and equipment usually consists of Design Qualification - DQ , Installation Qualification - IQ , Operational Qualification - OQ and Performance Qualification - PQ . 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 (DIY) assemblies (i.e., cars, computers etc.) 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. At the same time, one should bear in mind to kindly share the original work with others, if the activity, especially validation of newly invented machinery/equipment, is worth of publishing.

Qualification of machinery/equipment is venue dependent and re-qualification needs to be conducted once the objects are relocated. The full scales of some equipment qualifications are even time dependent, and hence re-certification is necessary when a specified due time laps 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, or an ini file etc, have been necessary. In such a situation, the specifications of the parts/devices/software and restructuring proposals should be appended to the qualification document whether the parts/devices/software 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 parts/devices/software 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 ^{[8], [9]}. 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 verification & 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 functional properly and which meet the safety standards . Some examples could be legislative rules, guidelines or proposals , methods , theories/hypothesis/models , 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 validating of

• ancient scriptures that remain controversies
• 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 laps. 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 (OOS) 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 monographes of USP and BP to cater for domestic needs

• 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 an chemical assay by a skilled operator with multiplicated online system suitability testings