Software Development Guideline: Why Does Software Have Bugs?

According to a 2002 study from the National Institute of Standards and Technology, software bugs cost the U.S economy about $59.9 billion each year. And that was two decades ago.

Now we’re living in industrial 4.0, where technology like software is indispensable. The Boston Globe revealed that the cost of a failed project for the information technology industry was approximately $84 billion. 

One of the common reasons why a project fails is because bugs occur in software. The IEEE Software Magazine reports that leading software development companies eliminate about 95 percent of all known bugs before releasing products to their customers. However, the industry average is below 85 percent.

No software is 100 percent bugs-free. Bugs are common in all types of software, from applications to systems to programs. If you don’t deal with them early enough, they can ruin your software, not to mention your company’s reputation.

These issues lead to a question: Why do bugs happen? How can we effectively prevent them from affecting our product and brand image?

This article will provide you with information answering those questions.

What is Bug?

First of all, you’ve probably heard of terms like bugs, defects, errors. These issues are look-alike in manner, but actually, there are differences. And because this article focuses mainly on bugs, we would like to dedicate this session to understand better what bugs are. We can implement practical solutions to minimize bugs’ presence and the damage it brings. 

As mentioned in the previous article about software testing life cycles (STLC), the software testing and QA phase is vitally important. The testing phase is also the phase of identifying defects.

Errors are mistakes, misunderstandings, or misconceptions of software developers; in simpler words: a mistake in code is an error. Errors found by testers are defects.  A defect is a difference between actual and expected results. Defects accepted by the development team are bugs. Bugs can be seen as “a glitch”, causing the program to operate differently and incorrectly from its creator’s intentions. 

For example: during the testing phase, the tester enters a valid email address, but somehow the system shows a warning of an invalid email. The tester then reports to the developer. When s/he accepts that defect, the defect is now a bug.

Why does software have bugs?

Many reasons are leading to bugs. Let’s have a look below:

1. Human/Developers' Mistakes

Working with inexperienced developers can lead to a program with many bugs as the developers may lack the necessary skill set. This is why it is critical to implement a rigorous testing process when hiring both internal and offshore software outsourcing teams. Besides being interviewed to assess both soft skills and technical skills that may include programming tests, you should consider looking at their experience.


Typically, this includes reviewing past projects and ratings from past customers to ensure they have general expertise in the development and have worked on similar projects before. 

2. Miscommunication

Many of the time, bugs occur due to unclear communication between the business and the software development team. If the company does not / has not clearly defined and states the team’s requirements at the beginning of the project, the software development team will have difficulty meeting them and leading to a "fail to function" product according to the business leader’s vision.

To achieve the desired results, businesses must carefully communicate their requirements and goals to the development team. Having everything on documents is highly recommended so that people can analyze the conditions better. This way, developers can understand what their clients want and can build a complete product. All stakeholders must communicate regularly throughout the project to ensure the ultimate success of the project.

3. Inadequate project’s timelines

Everyone wants to be the pioneer who enters the market with the next generation of innovation. However, it takes time for the software development process to go in the right direction. Any attempts to rush will put you at risk of getting bugs (more than it should have been) or not discovering them, which ultimately leads to severe consequences.

As one of the top software development companies in Vietnam, TP&P Technology's experienced development team will help you get your project done on a reasonable timeline with as few bugs as possible. Our team will tell you if your project timeline is realistic or not and give you the best estimate of how long it will actually take. 

4. Project changes too often

Of course, your requirements don’t have to be unchangeable. Things happen. Flexibility is needed, especially in Agile methodologies. However, if possible, you should define your requirements before the project is officially launched as straightforward as possible and avoid making changes, especially its core parts. Frequent changes are confusing to developers and involved stakeholders. One change can affect another, leading to more bugs appear.

If the requirement needs to be changed, as a business leader, you should ask your development team how this change will affect the product as a business leader. 

5. Wrong tools

Using third-party tools can accelerate the development process and make it easier. However, developers and businesses should ensure that these tools, like libraries, frameworks, etc., are helping. Sometimes, these tools can bring bugs to the software.


Additionally, the development team must be careful to keep these tools consistent throughout the project’s duration. Frequent conversions can also lead to bugs.

6. Insufficient or lack of QA testing

QA testing is the best way to ensure the product’s quality in terms of performance, usability, and functionality. If you skip this phase or inefficiently employ it, your product/software may carry bugs.

QA testers must play a separate role from the developer. They are responsible for performing various tests to make sure that the product is performing as expected. At the same time, they must report any bugs that could affect the user experience.

7. Lack of documentation

Software developers always have to document their code when building a product. Without the right documentation, they will have difficulty to modify or build upon the project to complete it. It can also lead to bugs if the code is not well documented. 

The best advice we can give is to write clear, easy-to-follow code from the start. Code that is too complex often introduces bugs to your software because other developers have difficulty in reading and understanding it. 


Above are 7 common reasons why bugs occur in software. Once again, it is not possible to guarantee that one product is free of bugs. However, understanding the core reason and what it is can help you prevent, and minimize the occurrence of these flaws and their interference with the quality and success of your software.

We are a team of software development outsourcing experts, who have years of experience in building software and running software testing & QA test. We provide software development services to clients from many industries including blockchain, healthcare, eCommerce, etc.

If you have any questions about custom software development, drop us a line so that we can help you coding your dream!