Verification Vs. Validation: What Is The Difference?

By Indeed Editorial Team

Updated 19 September 2022

Published 28 April 2022

The Indeed Editorial Team comprises a diverse and talented team of writers, researchers and subject matter experts equipped with Indeed's data and insights to deliver useful tips to help guide your career journey.

Testing is an important part of the software development process, which enables developers to continuously monitor, identify and rectify errors in the code. Verification and validation are two aspects of software testing that developers use to test the developed program at different stages, especially while implementing the Agile methodology. Knowing about the differences between verification and validation can help you understand these processes better and practice them effectively. In this article, we discuss verification vs. validation, understand both the processes, look at their differences and when to use them and understand their importance in Agile development.

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Understanding Verification Vs. Validation

Understanding the key aspects of verification vs. validation can help you determine when to use which process and how to use them to ensure efficient software testing. Verification is the process of verifying all the elements of software development, including codes and documents at every stage of the development. Validation means checking whether a developed program meets all the requirements. Both processes are essential in software testing to ensure the product or software meets all the requirements specified by the clients.

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What Is Verification?

Verification is the process of performing checks to verify that the software under development meets the development standards and the client's requirements. It is a continuous process and can happen in multiple stages of software development. Developers may use a checklist to note the verification steps and perform them at the intended stage. This allows them to identify errors in the software's code and deviations from the client's requirement and fix them immediately.

Apart from software development, verification can be used for various purposes. For example, companies may conduct employee verification or background checks to vet an employee before onboarding them. Manufacturing units also use various verification methods to ensure their products are free of defects. In any area, verification is done from the beginning of the development process till the product is fully developed.

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What Is Validation?

Validation is the process of testing a software or product's completeness and whether it works as per the guidelines and requirements defined by the client. Validation is a one-time process and generally happens after the software or product is fully developed. Usually, the developers validate the end-product, but sometimes companies may ask actual customers to perform the validation and provide genuine feedback. Companies do this by asking their customers to enrol in a beta testing programme, where they use the product or software over a period of time. They may then report any issues or suggest enhancements.

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Differences Between Verification And Validation

While both processes check whether the product meets the client's requirements there are several differences between the two. Here are some significant differences between verification and validation:

Development stage

Developers perform verification and validation in different stages of software development. They perform verification checks in each stage of development, be it in the middle of a stage or right before moving the code to the next stage. This allows them to identify any errors in the code or changes and address them early in the development process. This can help avoid any major issues from occurring in the later stages.

Developers typically perform validation at the end of a development process, when the software is fully developed. Testing the product after it is developed can help you determine its functionality and compatibility with different types of systems. It can also help in identifying any missing features or enhancements to the existing ones before releasing the product to the customers. Only when the product passes all the validation checks and meets the client's requirements can it be released for public use.

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Type of check

Verification and validation use different types of checks to determine if the software meets the client's requirements. Both processes can work well with manual or automation testing. You may use a comprehensive checklist to perform verification on separate pieces of code. After that, you can combine pieces of code together and very if they work well together. Verification also includes checking documents and designs related to the product. It may not involve any code execution throughout the verification process.

Validation involves checks related to the actual product. It aims to test if the final product is performing the intended function in the desired way. For example, you may see if a submit button on a webpage actually submits the user information to the database. These checks may also involve testing functionality with different types and amounts of data to see how the product behaves. All these checks typically involve code execution.

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Purpose

At a high level, the purpose of both the processes is to ensure a working software. Individually, the purpose of verification is to check each element of the development process to determine if the team is building the product right. The purpose of validation is to determine if the team is building the right product.

Timeline

In the development timeline of software, verification comes before validation. You require verifying the components of the product and determining if it requires any change or if you can move it to the next stage. Once all the components pass the verification checks, you can combine them into one product and perform validation checks on it. Completing verification before validation is vital to ensuring you do not miss any critical bugs that may be difficult to find at the end of production.

Agile Development Process

Agile development is a process where companies develop a product through continuous integration. They generally divide the client's requirements into several equal parts based on the functionalities and develop each part individually. In Agile development, companies deliver these finished pieces of functionalities to the clients for review. This allows the clients to provide feedback and ask for any changes in a particular piece before the company starts developing another piece.

As the pieces are developed, the development team integrates them and check how each new integration behaves when combined with the previous ones. In Agile methodology, verification and validation play a significant role in ensuring product quality. Each piece of functionality goes through verification and validation, unlike traditional development, where validation happens only once. The development team also performs validation upon developing and integrating the entire product.

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When To Use Verification?

Verification is widely used in the software development industry. It is used in testing software for correctness and to check the design, database, software architecture and code for errors and changes. You can start using verification checks right from the beginning of product development. You can perform verification even after completing a validation. If a final product requires changes, it may go through the development process again to implement that change. During this process, you may verify the code developed to incorporate the change into the final product.

When verifying the quality of a product, you might inspect the code and walk through the current state of the product to ensure it makes sense. Doing this may allow you to see whether the code might work the way you want it to and can help you prepare for a more efficient validation process. For Agile development processes, you can use automation scripts to automate the verification process and reduce the time to complete the checks for each integration.

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When To Use Validation?

Validation is typically a process to check the completeness of a product. You can use it at the end of the development process. Validation requires testing from the end user's perspective, hence it is important to develop the product completely to perform validation. While you can use validation for companies that test physical products, it is often best to automate validation processes for software development because many companies work with multiple complex products at once. It is also usually a good idea to use both verification and validation techniques together to ensure each product fulfils both various needs and requirements.

Using the established needs of stakeholders, you can create a series of automated tests that run a piece of software and measure if it performs an action, then have it notify you about the outcome. This way, you can understand where a piece of software might fail and look at the code to fix it. Automating the validation process may also allow you quicker checks and accurate results.

Applications Of Verification And Validation

Verification and validation can be useful in a lot of fields. Their application can help in ensuring quality product development. Many industries besides software development and technology can benefit from verification and validation processes. Some of these industries include:

  • Health care

  • Food science

  • Agriculture

  • Finance

  • Pharmaceuticals

  • Science

  • Engineering

  • Manufacturing

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