Software verification and validation

Imagine that you finished a big, big, BIG project. You’re delivering it. The client sings the final check and shakes your hand, thankful. Two weeks later, you receive a call. It’s your lawyer. Your client wants to sue you because what you did is not what he asked for (at all). So… you have three choices: a) you rot in jail, b) you deliver a new product (that means, you work extremely in order to make it fast and good) or c) you travel back in time and check that what you’re developing is actually what the client needs. I have great news! Although option C is physically imposible, you can do something similar: do it before every project you build.

Verification and validation may seem the same concept. To identify the difference, ask yourself: am I building the product right? This is verification. In the other hand, am I building the right product? This is validation. Both are equally important.

There are three other concepts that are important. One might think they’re all the same, but they’re not. Here are the concepts about errors:

  • Fault: when your code is wrong, when you forgot a parenthesis, when you named the file with a wrong extension. Simple bugs, generally debugged by the IDE or compiler iteslf.
  • Failure: runtime error. It happens during execution of the program. These must be debugged manually.
  • Malfunction: this is a deeper error. It involves the structure and architecture of the program. Usually, this are the worst bugs. These take days to be solved. Sometimes one must restructure from zero.

This process is directly related to software testing and requirements elicitation.

flickr photo by West Point - The U.S. Military Academy shared under a Creative Commons (BY-NC-ND) license
flickr photo by West Point – The U.S. Military Academy shared under a Creative Commons (BY-NC-ND) license

Software Verification and Validation


Verification and Validation are important during the Software Lifecycle because they help us to find and correct errors as soon as possible, thus preventing the delivery of a faulty product to a costumer. Is it a good product or not?

There are two aspects of V&V tasks:

  • Confirms to requirements
  • Fit for use

It’s important to outline the difference between these two terms:

  1. Verification:
    1. Process to evaluate the mediator products to check wheter the products satisfy the conditions imposed during the beginning of the phase.
    2. “Are we building the product right?”
    3. It uses static testing.
    4. A verifier stablishes that the product implements all the requirements documented in the SRS.
  2. Validation: 
    1. Process of evaluating the final product to check if it meets the business needs.
    2. “Are we building the right product?”
    3. It uses dynamic testing.
    4. The validator establishes that the SRS is a true reflection of the user’s needs.


Software Verification and Validation

Validation and verification are two different concepts in software engineering, each one can be abbreviated to the questions: are we building the right system? and are we building the system right?


Validation is concerned with checking that the software actually satisfies the customer’s needs and its objective is to demostrate that the product fulfills its intended use when placed in its intended enviroment, whereas verification is the process which checks if the software is functioning correctly and its objective is to ensure that work products meet their specified requirements.


The difference between Verification and Validation

Verification vs Validation

Software Verification VS Validation

First off, verification & validation are two terms that are common used in software development. They are commonly mistaken as if they were equal. Let’s begin by defining each term.


Verification is an evaluation of the process of creating a final product. It is useful to determine if the project development goes in the right track. Intermediary work is analyzed: documentation, data bases, etc.


  • Review of requirements
  • Review of design documents, including HDL and LDD
  • Code review
  • Documentation review


It is the process of evaluating the final product to determine if it matches the user needs. Basically all types of testing post-development are considered validation.


  • Prepare test requirements documents and other test specifications to analyze results.
  • Evaluate if these results is fit for use and reflects the project requirements.
  • Test for complicated values, stress, and all possible functionalities.
  • Check if errors exist, if they do, if a graceful message explain them.
  • Check business requirements, and if it is fit for it.

Video explanation:


Software Verification and Validation

Although validation and verification might mean the same, they are two different concepts that are used in software engineering.  Just to avoid confusion, everything can be narrowed to this:

Validation: Are we building the right system?

Verification: Are we building the system right?

It is true that both of them require approval, but it dependes on the type of approval you need. Validation checks that what is being done, is what we need. This has to do with complying with the requirements that are proposed by the project managers. Verification, in the other hand, is to check that what we are doing, is being done the correct way. It is all about complying the requirements, so everything converges on reading the requirements the good way.

I’m might contradict myself a bit, but verification and validation do have things in common. These are processes in order to assure software quality and guess what, it also has to do with software testing and evaluation. This is a diagram of what could comprehend each of the concepts, and also what they do have in common.


Credit to Easterbrook, from here I obtained most of this content.

Software Verification and Validation

There is a big difference between the verification of Software and the validation it. Also, there are some similarities between both of them. First, verification is the process which checks if the software is functioning correctly. On the other side, validation is concerned with checking that the software actually satisfies the customer’s needs.

Verification checks the quality of the software such as testing, inspection, design analysis, specification analysis, etcetera. All the processes should be objective because there is needed to be a concise product. If the software is created with the correct specifications, there might not be subjective judgements to it.

Validation is the process of checking if the stages of the creation of the software are accomplishing the customers needs.Validation is a subjective process because analysis might vary between the people that are evaluating the project. It all depends on the evaluator and the different ideas between each evaluator.

They have differences, such as the following:


(Retrieved from

The development of a project needs both of them, they might be different but important. As an example, applying both onto a project is like comparing the design of a webpage and the code. Code is fundamental to make the webpage work, but if the design of it isn’t the best, the webpage might be useless or it isn’t going to meet the customer’s needs.

Carlos Pedraza

Miguel Cabral

Victor Najar

Juan Pablo Ramírez

Information retrieved from