Hi there! If you’re new to software testing, you may have heard the terms “verification” and “validation” thrown around a lot. At first glance they seem nearly identical, but there are some important differences between these quality assurance concepts that are good to understand.
In this comprehensive guide, I’ll overview what verification and validation entail, when you should perform each, as well as tips to implement them effectively based on my 10+ years of quality assurance experience.
What is Verification and Validation in Software Testing?
Let’s start with a quick definition of each term:
Verification refers to the process of methodically reviewing and evaluating software artifacts like requirements docs, technical specifications, the software architecture, code, and other project documents to confirm they meet predefined standards and correctly implement all the explicitly stated functional elements and non-functional requirements.
Validation refers to rigorously testing the final integrated product to determine if it performs as expected and meets the true user needs in the targeted environment. Validation ensures the end product aligns with real-world demands and use cases, providing the expected value to the end-user.
In other words, verification is about building the product right according to the approved specifications, while validation focuses on whether the team built the right product that fulfils actual user needs.
Why Do Verification and Validation Matter?
You might be wondering why you should bother with these intensive verification and validation activities that require extra overhead. What are the actual benefits?
Research from IBM indicates that the cost to fix bugs grows exponentially the later they are detected in the lifecycle. While a coding error found during code reviews costs on average $100 to repair, that same bug could cost over $15,000 if discovered after deployment!
This graph illustrates the increasing cost:
Source: https://www.ibm.com/blogs/rational/wp-content/uploads/sites/2/2019/07/Picture1.png
By identifying defects early through verification techniques and stopping them from flowing downstream where they can lie dormant and increase rework costs, teams can realize major cost savings.
Additionally, a survey from Perforce found that 67% of respondents cited software quality as their top metric of project success. Verification and validation techniques enhance quality by systematically removing errors and ensuring adherence to specifications.
Let‘s explore in more detail how verification and validation accomplish this…
Key Differences Between Verification and Validation
Now you know why V&V in testing is worth prioritizing. As mentioned, while verification and validation sound pretty similar, there are some notable differences:
| Verification | Validation |
|---|---|
| Focuses on checking raw work products like design documents and code against predefined requirements and standards | Carefully tests the finished, integrated product regarding how well it meets user expectations |
| Done iteratively by developers, testers and other stakeholders at each stage of development | Mainly done by QA testers after development finishes |
| Leverages reviews, walkthroughs, traceability mapping and static analysis | Relies on dynamic testing techniques applied to application |
| Targets specs, architecture plans, source code, etc. | Targets the integrated product released to users |
So in summary:
- Verification measures how well the product conforms to original specifications
- Validation checks whether the final product will provide genuine value to users
Next let’s explore when to leverage verification vs validation…
When Should You Perform Verification vs Validation?
When to use verification
Because verification is focused on evaluating work products against predefined requirements, it should be conducted frequently and iteratively throughout the development lifecycle.
For example, before any code is written, you or other team members should double check that the requirements documentation is comprehensive by going through it with a fine tooth comb to verify all elements are captured before proceeding to design.
After development of foundational architecture and frameworks begins, regularly perform structured walkthroughs of the design diagrams, entity relationship mappings, wireframes and other artifacts to ensure they conform to specifications. Track any defects using a traceability matrix that maps requirements to test cases.
During coding, developers should be continuously desk-checking their code before compilation to catch logical bugs. Peer code reviews should also happen frequently where team members inspect each other’s source code for issues.
When to use validation
Whereas verification corresponds to actively monitoring outputs during development before product construction finishes, validation testing relates to rigorously evaluating quality after you’ve built the complete solution, similar to test driving a car off the factory floor.
Validation testing techniques like system testing, user acceptance testing (UAT), integration testing, performance testing and others are done later in the lifecycle to verify the completed software works properly in real-world use cases.
Often this testing phase is handled by a quality assurance team separate from the core product team. The QA professionals design test cases that correspond to key user scenarios and execute them on the finished, integrated product while monitoring the results.
By validating the final build through dynamic testing rather than just reviews, you can catch lingering issues that may have slipped by during earlier verification checks. Let’s look at recommendations for performing verification and validation effectively.
Best Practices for Verification Processes
Here are some top principles and techniques to consider for verification:
Leverage checklists for requirements reviews: Create standard templates listing all elements that must exist for areas like functional requirements. Cross-check during analysis.
Perform code walkthroughs: Step-by-step code reviews to detect bugs early. Explain intent to reviewers before going through it.
Implement desk checking: Dev best practice of manually reviewing own code logic before testing to find errors.
Automate when possible: Static analysis tools can automatically scan for code quality issues and flag items for human review.
Conduct traceability mapping: Cross-reference specs to test cases in a matrix. Ensure every defined requirement has corresponding tests.
Adhere to standards: Follow consistent style guides, patterns and documentation templates to ease verification.
Start early / integrate often: Begin reviews in analysis and perform regularly to detect defects before significant rework is needed.
Include diverse perspectives: Business, development and testing insights help account for blindspots.
Best Practices for Validation Processes
Validation encompasses various forms of testing applied to completed product builds. Here are some key things to consider:
Simulate real-world scenarios: Construct test cases modeling common user workflows under different conditions. Prioritize complex core functions.
Define measurable pass/fail criteria: Establish quantifiable metrics aligned to business objectives for test success/failure to prevent ambiguity.
Leverage test case management tools: Enables you to link tests to requirements and defects while tracking execution for reporting insights.
Automaterepeatable test cases: Automation frees up time for testing edge cases. Leverage tools for test parallelization.
Perform cross browser testing: Validating consistency of UX across browsers like Chrome, Firefox, Safari catch rendering issues.
Focus on high risk areas first: Target complex functionality and mission-critical flows before nice-to-have elements.
Get user feedback early: Conducting user acceptance testing with a pilot group early allows incorporating suggestions.
Monitor system performance: Use tools to simulate high traffic conditions and measure speed metrics like response times and load capacity.
Verification vs Validation – Key Differences Summarized
Let’s do a quick recap of the main verification and validation differentiators:
| Area | Verification | Validation |
|---|---|---|
| Performed By | Developers, testers, BAs, PMs | Mainly separate QA testing team |
| Objective | Confirm adherence to standards | Prove software works as intended |
| Frequency | Continuous throughout dev lifecycle | After finished product gets built |
| Methods | Checklists, walkthroughs, reviews | Testing end product like UAT |
| Target | Design documents, code, specs | Integrated product released to user |
| Goal | Build product right | Build the right product |
So in summary, verification and validation may sound similar but have distinct objectives. Verification acts like building a house right with proper materials and architecture while validation ensures the final house meets the expectations of home buyers!
Conclusion
I hope this beginner’s guide gives you a helpful introduction to verification and validation in testing! While performing comprehensive V&V requires some extra overhead, putting in place the right verification checks early and often combined with rigorous validation testing of the finished product goes a long way towards releasing a high-quality software application that exceeds customer expectations.
Let me know if you have any other questions!
