Striking the Balance: Finding the Perfect Ratio of Manual to Automation Testing

By Rabina Jusufovic, QA Test Automation Engineer & Team Lead @ Authority Partners

Automated testing is a powerful tool that can boost efficiency and effectiveness in software testing. It can expand the scope and depth of tests to improve software quality, execute lengthy tests unsupervised, examine an application’s internal program states, data tables and file contents, and simulate a controlled web application test with thousands of users.  

However, it is important to keep in mind that manual testing is complementary to automated testing, as it finds problems from the viewpoint of the user or unanticipated bugs from unplanned scenarios. This blog assesses the key differences between manual and automated testing, the importance of both methodologies in software testing and how they can be successfully combined. 

We frequently question the need for automated test cases in today’s lightning-fast world. Defects still occur even if the majority of software organizations (at this point in time) include some type of quality in the product delivery process. Even with the most thorough test strategies that involve significant manual testing efforts, defects somehow manage to either creep up or reemerge like mystical underworld creatures, despite test engineers’ best efforts to catch them before the release. With this being said, automation comes in as a nifty tool.  

If applied properly, test automation is the ideal way to boost effectiveness and efficiency since, as we all know, time is money. Another important aspect is that manual testing is done by a human, and we’ve all experiences human error at some point in our lives (not to suggest that our automated test cases are infallible; at the end of the day, they do what they’re told). 

Manual and Automated Testing: What’s the Difference? 

We all know that tests must be run repeatedly throughout the development lifecycle to ensure the highest level of quality. We repeat the test cycle whenever the source code is modified, and depending on the product, different testing environments may be needed to support various operating systems and hardware configurations. We can all agree that testing a product manually is both expensive and time-consuming, but automated tests can be run frequently with little additional cost (that we add to maintaining them) and are also significantly faster! 

Automated software testing can expand the scope and depth of tests to improve the quality of any software. It is possible to execute lengthy tests unsupervised, which is not the case with manual testing. Even more, machines with various setups can run them. Automated software testing can examine an application’s internal program states, data tables and file contents to check if everything is functioning as intended (this requires major manual labor). Every test run can easily include the execution of hundreds of distinct complicated test cases, giving test coverage that is not achievable with manual tests. 

During tedious manual testing, even the most meticulous tester will make mistakes. Every time they are run, automated tests carry out the same exact processes and never forget to capture thorough results. The time saved from not having to repeat manual tests allows testers to develop new automated software tests and work with complicated features. 

A controlled web application test with thousands of users cannot be carried out, not even by the biggest software and QA departments. Tens, hundreds or even thousands of virtual users interacting with a network, software or web application can be simulated through automated testing. 

All in all, the question of why we require both manual and automated testing naturally emerges. Why don’t we totally transition to automation if that’s the best course of action? Another question is: why haven’t we done so already? 

Although automated testing typically improves testing uniformity and speed, it is only as effective as the scripts you create. In order to find problems from the viewpoint of the user or unanticipated bugs from unplanned scenarios, etc., manual testing is complementary to automated testing. Along with effective automation, there is a great need for human testing heuristics. 

When you use a combination of these tests to cover various aspects of the same feature, when manual tests pick up where automation left off, when there are tests that are only “semi-automatic” or when manual intervention is required to move on to the next automation set of tests are just a few examples of how automated and manual testing can be successfully combined. 

The new reality of agile and DevOps requires a new strategy, where testing leaders must coordinate testing efforts across all testing tools and approaches, starting with manual testing (scripted and exploratory), moving through the team’s functional automated efforts and ending with unit and integration tests run by a CI/CD framework. 

Now that we’ve asked ourselves this question, the response is that there isn’t a single, correct answer because it heavily relies on the product you’re working on. However, let’s provide some guidance on what to consider while making those judgments. 

The Limitations of Automation and the Need for Human Testing 

Let’s look at the changes to the development and testing processes.  

We’ve become agile, which relies on shorter cycles and demands ongoing stability. We’ve shifted to the principles of CI/CD based on continuously developing and testing a system. 

Additionally, DevOps has entered our realities, which is no longer just restricted to development, but also extends to testing the deployment procedures. 

All of the aforementioned results from the increased need to expedite processes and enable quicker releases. 

Even though automated testing is becoming more popular, manual testing is not going away. In actuality, each sort of testing performs a distinct role in the QA process, and when combined, they in some way enhance one another. Let’s quickly review the key distinctions between manual and automated testing in order to comprehend this. 

Understanding the differences between the two methodologies and how they differ in execution, implementation and the scope of test/quality coverage are important considerations when making a choice. 

Let’s start by looking at the goal of the tests:  

  • Manual tests are used to assess the product’s quality, value, user experience, etc., as well as to identify flaws and potential improvement areas.  
  • Automated tests are used to monitor changes that could indicate problems as well as to maintain the product’s functional and non-functional stability.  

The contrast between the two is difficult to acknowledge, yet it is nonetheless necessary. 

The second, and most important, tip is to pay attention to the test’s nature. 

While writing manual tests is (relatively) inexpensive, running them costs money (hiring & training testers, time, getting familiar with the process of a specific environment and learning business logic, etc.). Unlike automated tests, which costs (relatively) more to write but less to execute. 

Other aspects to look out for include: 

  • Execution time: This is frequently longer for human tests and shorter for automated ones. 
  • Coverage: Manual tests are easier to alter and adapt because they frequently cover higher-level requirements and functions. On the other hand, automated tests frequently cover lower-level tests and are rigid (unless re-written). 
  • Results: Manual tests are directly related to the tester who conducted them. In contrast, automated tests are not affected by the tester or any other “human subjectivity.” 
  • Scalability: Manual tests usually develop slowly and in accordance with the needs of the product. In contrast, the number of automated tests tends to increase over time. 

Finally, let’s examine the results of applying each in the SDLC.

Combining Automated and Manual Testing: Successful Ways to Blend the Two methodologies 

Compared to automated testing, manual tests often require fewer runs and repetitions. It goes without saying that the QA team members distribute and carry out manual tests. In contrast, automation frameworks are used to execute automated testing. Manual tests that result in failures are typically reported as bugs. Finding the sources of errors in automated testing frequently necessitates analysis and review. With manual testing, the actual findings are what are interesting, whereas with automated tests, the trends and benchmarks are what are interesting. 

Consequently, these factors are crucial when developing the ideal ratio: 

  • Recognize that these are quite distinct entities; determine your validation aim so that you can make a decision with much less difficulty; determine the type of testing that must be done. 
  • Plan for the number of runs; obviously, anything that might be repeated frequently is a good candidate for automation. 
  • Determine whether the testing effort is time sensitive. (No, this doesn’t necessarily mean manual testing is the best option; all previously stated points should be taken into consideration.) 


In conclusion, automation is the way to go for software testing. While it requires a lot of work upfront, the benefits in the long term make it worth the effort. It’s important to keep in mind, though, that they do require far more upkeep than manual test cases and aren’t necessarily a sign of a bug. If testing error is removed from the equation, manual runs that fail typically indicate a bug. In general, the quantity of failed tests during manual execution correlates with the quantity of bugs discovered. Automated tests typically result in more failed tests and false negatives than they do true issues. However, I still opt for the latter to do most of the work. Having a stable regression suite and implementing manual testing when and if needed, as well as having manual testing as a magic wand that comes out to play on occasion, could be the best of both worlds.