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Mahesh - RSREC

During and after the implementation process, the program being developed must be checked to ensure that itneeds its specification and delivers the functionality expected by the people paying for the software.Verification and validation is the name given to these checking and analysis processes. Verification andvalidation starts with requirements reviews and continues through design reviews and code inspections to

product testing.Verification and validation is not the same thing; although they are often confused.Boehm expressed the difference between them:

Verification: Are we building the product right?Validation: Are we building the right product?These definitions tell us that the role of verification involves checking that the software confirms to itsspecifications. One should check that it meets its specified functional and non functional requirements.Validation, however, is a more general process. The aim of validation is to ensure that the software systemmeets the customer’s expectations. It goes beyond checking that system confirms to its specifications toshowing that the software does what customer expects it to do.The ultimate goal of the verification and validation process is to establish confidence that the software system is‘fit for purpose’.The level of required confidence depends up on following factors:1. Software function: The level of confidence required depends on how critical the software is to an

organization.2. User expectations: Since from 1990’s the users have high expectations of their software. They are not willingto accept the system failures. So, software companies must devote more effort to verification and validation.3. Marketing environment: When a system is marketed, the sellers of the system must take into accountcompeting programs, the price those customers are willing to pay for a system and the required schedule for delivering that system. Where a company has few competitors, it may decide to release a program before it has

been fully tested and debugged because they want to be first in the market. When the customers are not willingto pay high prices for software, they may be willing to tolerate more software faults. All of these factors must beconsidered when deciding how much effort should be spent on verification and validation.With in verification and validation process there are two complementary approaches to system checking andanalysis:1. Software inspections or peer reviews: In this process the person will analyze and check systemrepresentations such as the requirements document, design diagrams and the program source code. They can useinspections at all stages of the process. Software inspections and automated analysis are static verification andvalidation techniques as it don’t need to run the software on a computer.2. Software testing: Software testing involves running an implementation of the software with test data. Itexamines the outputs of the software and its operational behavior to check that it is performing as required.Testing is a dynamic technique of verification and validation.

Inspection Process