Ensure that the right functions are performed Ensure that the these functions are performed right and are reliable

1. System testing, where the focus is the overall set of system functions to be provided to users; 2. Acceptance testing and beta testing, where the focus is the assessment of software acceptance or performance by users; 3. Usage-based statistical testing, where the operational environment by target users is simulated during software testing before product release; 4. Software fault tolerance, which focuses on providing continued service expected by customers even when local problems exist; 5. Software safety assurance activities, which focus on providing the expected accident-free operations or reducing accident damage when an accident is unavoidable.

 Check the conformance of a software system to its specifications.  The assumption is there is a well-defined set of specifications  All activities dealing directly with faults, errors or error sources

 Many specific QA activities deal with both the verification and the validation aspects.  Different types of testing can be classified either as verification test or validation test or contain both elements.  The focus of the acceptance test is clearly validation, while that for unit test is verification.  System test contains both the verification and validation components.

 The inspection is an important defect reduction activity is similar to testing above.  Inspection is more closely connected to verification than to validation.  For example, most of the inspection activities are performed on software code or design, which are classical verification activities.  The less used requirement inspections and usage scenarios based inspections are closer to validation.

 Defect prevention deals with error source elimination and error blocking  Both verification and validation deal with failures and faults.  For example, if the target is eliminating ambiguity in the requirement or the product domain knowledge, it is indirectly connected to validation.  If the target is to block syntactic faults or other faults due to the proper selection and usage of processes, methodologies, technologies, or tools, it is indirectly connected to verification.