Software testing, an integral part of software development, ensures that software products under development are free from bugs, in accordance with quality standards, and meet customer requirements. It is basically the total of the two activities – Verification and Validation (V&V).
V&V in software testing are two independent procedures that work together to verify a particular product meets specified requirements and satisfies its intended purpose.
Many people often get confused between these two terms and use them interchangeably. However, it is important to note that they are independent processes with different aims.
Verification is the process of examining the software product’s quality. In other words, it involves checking if the product meets the specified requirements and design specifications. In contrast, validation is about analyzing the software product to check if it meets customer requirements.
Without V&V, QA teams or testers can’t finish software testing. They are critical elements because they determine software products’ quality, reliability, and functionality.
This article will shed light on verification and validation in software testing and the detailed differences between them.
What is Verification?
It is the process of evaluating software development artifacts, such as documents, design, and code, to ensure that the product under development will comply with the specified requirements. As this process analyzes only the artifacts and not the end product, it is often referred to as static testing.
Specifications act as input to the software development process. Developers write the code based on these specifications. Verification checks whether the software code aligns or adheres to the specifications in every phase of SDLC.
The activities involved in verification are inspection, code reviews, technical reviews, and walkthroughs.
This process helps determine the quality of the software product but does not ensure that it will be useful. It is only associated with evaluating the product to check if it is free from bugs or errors.
What is Validation?
It is the process of evaluating the software product to check whether it conforms to customer requirements and expectations. In other words, it determines whether the product meets the client’s business requirements. It helps determine that the product has fulfilled its intended purpose in an appropriate environment.
Rather than evaluating the artifacts, the validation process evaluates the actual product. It is often referred to as dynamic testing. It is only concerned with the output and not about the internal procedures of the development process.
The activities involved in this process are functional and non-functional testing.
Difference between Verification and Validation
An American software engineer, Barry W. Boehm, describes these two processes clearly, which helps you understand the primary difference between them.
Verification: “Are we building the product right?”
Validation: “Are we building the right product?”
As you can see, these two statements are distinct, with a minor difference. The first statement implies checking whether we are building the product correctly according to the requirements and specifications. Conversely, the second statement implies verifying whether we are building the right product that meets its original intent or serves the intended purpose.
Verification vs Validation – A Side-by-Side Comparison
Though these processes are similar and contribute to the high quality of the end product, they are different. Let us now throw light on the difference between validation and verification in detail.
|The process of evaluating design, code, and documents to ensure that the product being developed meets the specified requirements.||The software product is evaluated to check if it conforms to the client’s business requirements and customers’ needs.|
|It checks the document, design, and code against the specified requirements.||It checks the reliability, usability, and functionality of the end product.|
|This process does not require code execution.||This process requires executing the source code.|
|Verification is often called static testing.||Validation is often called dynamic testing.|
|It follows a process-oriented approach.||It follows a product-oriented approach.|
|Answers the question – “Are we building the product right?”||Answers the question – “Are we building the right product?”|
|Errors found during this process require lesser cost/resources to fix than those found during the validation phase.||Errors found during validation require more cost/resources. Later the error is discovered, higher the cost to fix it.|
|It involves activities like document review, test case review, walk-throughs, and code inspection.||It involves activities like functional testing and non-functional testing.|
|Only the QA (Quality Assurance) team performs verification.||The software testing team and QA team together conduct the validation process.|
|It takes place before validation and in the early phase of the development process.||It starts only after verification completes.|
|Verification targets the internal aspects, such as design, database, code, requirements, and architecture.||Validation targets the entire end product.|
|It is all about the prevention of errors||It is all about the detection of errors.|
|Requires less cost.||Pretty expensive.|
Verification vs Validation – Example
Let us take a real-life example to understand these processes.
Consider going to a restaurant and ordering Blueberry Pancakes. How will you verify that the food you ordered is exactly what you want?
Firstly, you know how Blueberry Pancakes look. So, you start evaluating the dish by its appearance. You check whether:
- The food looks as you expect it to.
- There are blueberries around.
- It smells as usual.
This is nothing but verification, as you are not testing the actual product.
Now, if the dish stands true to the above parameters, you will proceed further to have it. When you consume the dish to check whether it tastes as intended, it is validation.
When Should You Verify and Validate?
These are independent and critical processes in software development to ensure that the product meets the specified requirements and fulfills the intended purpose. Both play a vital role in ensuring the quality of software products.
Verification occurs in the development process’s early stage, whereas validation is done only after verification. The former is used as an internal process, while the latter is an external procedure, as it involves the approval of stakeholders.
This was all about verification and validation in software testing. Both are critical and inevitable processes to ensure the quality, reliability, and functionality of software products. While Verification is concerned with building the product in the right manner, validation is concerned with developing the right product.
We hope this article has helped you understand the differences between these processes. If you have any questions feel free to ask in the comments.
Kuldeep is the founder and lead author of ArtOfTesting. He is skilled in test automation, performance testing, big data, and CI-CD. He brings his decade of experience to his current role where he is dedicated to educating the QA professionals. You can connect with him on LinkedIn.