bug management tools

Rapid technological advancements in the field of testing are facilitating QA teams big time. The primary example being the test automation which enables testers to execute multiple test cases simultaneously, test across multiple browsers and platforms, integrate with other popular tools and record test scripts for reuse. Yet, in spite of having such advanced bug management tools at their disposal, testers are often left wondering, “how did I miss this bug?”.  

It’s common for testers to miss out on bugs that come back haunting them if they let it slip through deployment. This poses a question, “Why do testers miss bugs?”. Experts believe that the problem has more to do with the testing approach rather than the advanced testing tools of today. Biases governing our minds can make us think irrationally or illogically which results in an error in judgment. These sets of biases are a result of past experiences and the term used to define this is a cognitive bias. Experts believe that missing bugs is nothing but an error of judgment caused by cognitive bias.

Cognitive bias can influence tester decisions regarding where to look for bugs, which functionalities would require a more intensive testing approach, how the user is likely to interact with the software or application, an assumption about the app based on who developed it, and the list goes on… So, let’s have a look at different types of cognitive biases that are most commonly found.

Confirmation Bias

The confirmation bias occurs when a person looking for information that validates his/her long-held beliefs. This restricts them to their own perspective and stops them from arriving at a logical conclusion. For example, this bias would make testers spend less time testing the code by a developer who he thinks writes impeccable codes.

In-attentional Bias

It’s when something is right in front of you and you miss it out. Simply because you’re not looking for it and giving a sufficient amount of attention. In QA’s case, a tester can miss out on bugs while focusing all attention on new updates and features.

The Negativity and Optimism Bias 

Opposites of one another, both biases can lead to unfavorable outcomes. Which bias applies to an individual depend on his/her general attitude towards life. The negativity bias makes an individual expect a negative outcome for every endeavor whereas the optimism bias makes him/her too optimistic. For a software tester, negativity bias can make him/her believe that it’s not possible to create bug-free software, affecting his motivation and ability to go the extra mile. Whereas optimism bias can make a tester believe that he/she can complete the task in half the time and this can make him/her miss out on important bugs.

The Congruence Bias

Limited to only a certain set of criteria in their mind, testers can deem a software to be error-free without even considering that those criteria might not be enough to form an informed opinion. Congruence bias makes testers test software only for the expected behavior, thus completely missing out on the aspect of negative testing. This way, they can never be sure if the software is behaving in ways it should not.

The Bandwagon Effect

When a person is influenced by the opinion of others, it’s called the bandwagon effect. In the testing world, a tester may be influenced by the opinion of his/her peers and may not spend much time and effort in testing software if the team members feel it is relatively bug-free.


Given biases with a brief explanation can help you understand how biases can affect testers’ rational thinking and force them to make mistakes. No matter how advanced bug management tools are, it’s the tester who has to test the software and determine if it’s ready for deployment. Therefore, it’s important to invest in training programs for testers.

Author Bio:

Ray Parker is an entrepreneur and tech enthusiast who loves to incorporate new technologies to get more efficient outcomes. When he’s not marketing his latest venture, he keeps himself busy in writing technical articles to educate peers and professionals.


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