Verification and Validation is the process of investigating that a software system satisfies specifications and standards and it fulfills the required purpose.
Barry Boehm described verification and validation as the following:
Verification: Are we building the product right?
Validation: Are we building the right product?
Roles of verification and validation in software life cycle
Verification requires several types of reviews, including requirements reviews, design reviews, code walk through, code inspections, and test reviews. The system user should be involved in these reviews to find defects before they are built into the system. Here is a table of every verification activity recommended in each stage of the software life cycle.
Software validation activities may occur both during, as well as at the end of the software development life cycle to ensure that all requirements have been fulfilled. Here is a table that shows the activities recommended for validation in any software project.
International standards for V&V of Software
IEEE Std for software verification and validation is established to set a common framework for V&V processes, activities and tasks in support of all software life cycle processes, including acquisition, supply, development, operation, and maintenance processes. Another purpose of this standard is to define V&V tasks, requiered inputs, and required outputs. Also to identify the minimum V&V tasks corresponding to software integrity levels using a four-level scheme.
This standard is organized into clauses, tables, figures and annexes. Each of them contains informative material, illustration, examples, mandatory requirements, process flow diagrams and more. It is complicated to extend all the information that can be found on this standard, so if you want to go depper feel free to go, here is a good pdf where you can find all the information about this standard and V&V in general.
IEEE Standard for Software Verification and Validation: https://people.eecs.ku.edu/~hossein/Teaching/Stds/1012.pdf
Role of V&V for each product must be determined by a project-by-project basis.This determination will be influenced by the criticalityofthe product, its constraints, and its complexity. In general, the objective of the V&V function is to insure that the product satisfies the user needs. Thus, everything in the product‟s requirements and specifications must be the target of some V&V activity.
To plan succesfully about V&V on a software problem you should focus on each verification and validation activity that was showed above. Just fit each of them on your project requirements and focus on the ones that you think your project needs the most.
Administration of a V&V Plan
V&V addresses software product quality directly and uses testing techniques which can locate defects so that they can be addressed. It also assesses the intermediate products, however, and, in this capacity, the intermediate steps of the software life cycle processes.The V&V process determines whether or not products of a given development or maintenance activity conform to the requirement of that activity, and whether or not the final software product fulfills its intended purpose and meets user requirements. When administrating your plan you should focus on the results, not the final results, the phase results. You must review each stage of the software life cycle in terms of verification and validation, so you can detect defects before they become a real problem. Try to follow an standard that helps to organize your plan and the administration of it.