Verification and Validation

Difference Between Verification and Validation

Verification and validation, popularly known as V&V are widely used quality control tests in SDLC. These terms are frequently used together, and some people even use them interchangeably. But in reality, they are quite different. 

Verification is the process of assessing the software’s quality, whereas validation is ensuring that all of the customer goals have been met. Software testing remains incomplete until both verification and validation testing is performed.

Failure to execute either can result in a faulty product, client dissatisfaction, or both. Therefore, understanding the distinction between validation vs verification testing is critical for assuring high-quality goods.

Don’t worry. This in-depth guide will help you learn everything you need to know to distinguish between these two quality control tests as well as how to successfully perform verification & validation testing.

What Is Verification In Software Testing?

Before diving into the difference between verification and validation in software engineering, first, let’s learn what verification testing is. 

Well, verification is the process of determining whether the end result of an SDLC phase matches the implementation steps properly. It verifies that the code logic adheres to specified system requirements.

Verification also checks to see if the product built can be linked back to the inbound objectives stated in the previous phase. This testing process answers one question ‘Are we building the product right?’.

Main goal of verification is ensuring system consistency, completeness , adherence to business standards, tech reliability as well as proper performance. It involves walkthroughs, reviews, and inspections.

 Verification In Software Testing

Advantages Of Verification Testing

  • Verification acts as the quality gateway at each phase of product development.
  • Ensures that the software being built meets the design specifications precisely. 
  • Helps to build software according to the customer’s requirements.
  • Verification detects bugs early & prevents defect leakage downstream.
  • Eliminates the high cost of later-stage defect detection & fixing. 
  • Gives developers, testers, and stakeholders better insight into the product.
  • Frequent verification paves the way to successful validation tests.

When To Use Verification Testing

Verification is the process of reviewing the intermediate work products of a software development lifecycle in order to determine whether we are on the correct route to developing the final result. 

Verification testing is used iteratively throughout the software design & development process. It helps to make sure that the designs are being followed precisely while development.

Before developing any new feature in the software, verification tests need to be performed. This test checks & reviews all the business, specification, and design requirement documents.

This must be done before starting development of every feature or aspect of the product to ensure that no guidelines are overlooked.

Verification is used before and during developing each & every module of software to ensure that the system is well-engineered and bug-free.

What Is Validation In Software Testing?

Validation is the process of assessing a software product at the end of software development for ensuring complete compliance with user requirements. It is a high-level dynamic testing process. 

The main question that validation testing answers is: ‘Are we building the right product?’. This quality test evaluates the end-product of SDLC to identify if it meets both the organizational goals as well as user needs. Additionally, it determines whether or not the system performs its intended functions and complies with specified requirements. 

Validation testing is performed after the software development cycle has been completed. It validates whether the client has received the expected product or not.

Validation In Software Testing

Advantages Of Validation Testing

  • Validation boosts the reliability of the final software product.
  • Defects missed during verification can be detected before deployment.
  • Confirms stakeholder requirements & expectations have been met.
  • Ensures proper integration of the product into the client’s desired environment.
  • Detects mismatch between end-product & client requirements, if any.
  • Based on validation test results developers can take corrective action if required.
  • Assures that software operates smoothly across various OS-browser-device combinations.

When To Use Validation Testing

Validation testing is typically used after a certain module is coded or after the entire software product has been completed. Its primary goal is to ensure that final product meets the needs of stakeholders and customers.

Validation tests are conducted by developers after a new feature has been added to the software. Unit tests, integration tests, and performance tests are a few of the validation tests. Each is used at a different phase.

For example, unit validation tests are executed after each unit of code has been written whereas integration tests are conducted after multiple such units have been combined together.

While these tests are done during development phases, performance validation testing is done at the very end of the development process on a completed software.

Difference Between Verification And Validation In Software Testing

To understand the difference between validation vs verification testing, you need to learn what each of them targets to achieve. Verification evaluates the intermediate products to inspect whether it satisfies the specific requirements of that particular stage whereas validation evaluates the end product to make sure it meets the business goals. 

The key point in verification vs validation in software testing is that the first identifies if the product is being built right and the latter checks if the right product is being built. 

Another point in validation vs verification testing is that validation is done at the end of the entire development process or after each module is completed but verification is done before & during the development.

Verification involves static testing such as reviewing & inspecting the software requirement documents, business requirement documents, as well as design documents.

This process ensures that the software being developed follows the intended specifications and isn’t being de-railed from the specified path. 

QA team performs this test without actually executing the software. Proper verification testing can detect maximum bugs and reduce defects in the later phases.

Validation testing, on the other hand, is performed by both the QA team and software developers. Because this testing actually involves executing the software and checking both internal & external features. It checks if the software works as per client requirements.

Difference Between Verification and Validation

Comparison Chart Validation Vs Verification

Verification is a low-level testing method to check if the software is being developed as per specifications documents.Validation is a high-level testing method to confirm that the software meets stakeholder & user requirements.
It is a static testing process including review of design and requirement documents.It is a dynamic testing process that validates the actual software.
Some verification techniques are code review, desk-checking, inspection, and walkthroughs.Some validation techniques are white box testing, black box testing, unit testing, and performance testing.
Verification doesn’t require code execution.Validation requires code execution for testing end product’s usability & functionality.
It is conducted by the quality assurance team.It is performed by both developers & quality assurance team.
Verification is run before validation.Validation is run after verification.
Verification testing targets Quality Assurance.Validation testing targets Quality control.
Identifies & eliminates defects in early development stage.Detects defects missed by verification testing.

Validation Vs Verification: Why Do We Need Both?

Verification and validation uses are manifold and we do need to perform both on our software product to ensure it conforms to specifications along with satisfying user goals.

A product can pass through the initial verification yet fail the validation test meaning the product doesn’t match the user needs. In such cases, even if the product is of high-quality it would fail to satisfy customers and the company would face heavy losses. 

On the other hand, if we skip verification testing, there is no way to ensure the software being built is following specified requirements. As a result, even if validation testing identifies requirement mismatch, you’d have to start over the development process and incur hefty financial loss.

Together V& V eliminate risks of product failure and ensures that the final software meets quality standard as well stakeholder expectations. Therefore, we need to conduct both verification & validation testing for ensuring the overall quality.

Validation & Verification  In Different Phases Of The Development Lifecycle

Every stage of the software development process includes verification and validation. Here’s a brief description of verification and validation uses in different SDLC phase.

Planning Phase

  • Contract verification
  • Concept document appraisal
  • Project risk assessment

Requirement phase

  • Software requirement assessment
  • Software interface evaluation
  • System & acceptance test strategy generation

Design Phase

  • Software design & UI evaluation
  • Component integration plan 
  • Test design generation

Implementation Phase

  • Source code & requirement document evaluation
  • Test case & test procedure generation
  • Test case execution

Test Phase

  • System & acceptance test execution
  • Update traceability matrix
  • Analyze outstanding defects

Operation Phase

  • Final test report generation
  • Assessment of unexplored constraints
  • Evaluation of proposed change

Maintenance Phase

  • Evaluate irregularities, migration, and retrial features
  • Validation of production issues

Examples Of Verification And Validation

To get a more clear idea regarding validation vs verification testing, let’s discuss a verification vs validation example. Let’s say there is a button named ‘Submet’ on a login page. 

In this case, verification checks the design documents and corrects the spelling ‘Submet’ to ‘Submit’.  If verification is not done, the developers would create a button called ‘Submet’. 

Once verification is done and the code for the button is ready, validation testing will be done. During validation, testers would discover that the button needs to be clickable. They’ll inform the developer team to make the button clickable. 

If validation is skipped, the button would not be clickable as a result customer would reject the product.

Frequently Asked Questions

What Are The Different Validation Approaches?

There are 3 main validation approaches. They are Internal validation, External validation, and Process Validation.

What Are The Main Verification Phases?

Requirement verification, design verification, and code verification are the main phases of verification testing.

What Is Walkthrough In Verification Testing?

Walkthrough is an informal method of product evaluation in which several teams examine the product and attempt to find any faults or other flaws.

Wrapping Up

Verification and validation are critical software quality tests that must be rigorously implemented in order to achieve the finest possible end product while also ensuring that it adequately fits customer requirements. Hence, understanding the difference between verification and validation in software testing is crucial. 

Both validation & verification checks whether the software is developed according to plan or not, one before beginning development and one afterwards. Simply said, verification relates to requirement review activities, whereas validation is the execution of real testing methodologies.

We have discussed all that you need to know about verification vs validation in software testing. Now, it’s time for you to properly apply these tests to verify and validate your software project.

Rahnuma Tasnim

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