How much are software bugs costing you?

lines of good quality code

Examining the cost of late bug detection in software development

Innovation is key and the competition is relentless in today’s dynamic IT landscape, which means there’s no room for inefficiency. Quality software development is not just about swiftly launching a product or service, it’s also about ensuring that what you deliver is of superior quality. A software bug isn’t merely an inconvenience — it’s a potential hurdle that can delay launches, inflate costs, and even tarnish the reputation of your brand.

Have you ever considered the real price of your software bugs? Not just in terms of immediate repair costs, but also considering the broader implications on your entire development process?

Appreciating the true cost of a software bug is the first step to catching them earlier and saving your business both time and money, but determining that cost isn’t easy…

The cost of bugs at different stages of development

As we navigate the complex journey of software development, it’s crucial to understand that not all bugs are created equal. This applies regardless of the delivery methodology adopted – Agile, Waterfall, Hybrid or any other. A bug’s impact and the cost of fixing it can vary dramatically depending on the stage of the development lifecycle in which it is discovered:

  • Requirement phase: If a bug is detected during the requirement definition and elaboration phase, the cost to fix it is relatively low. It usually involves modifying the requirements with little or no impact on other artefacts.
  • Design phase: Bugs found in this phase may require more effort to fix as they could involve changes to the software’s architecture or design patterns. However, the cost is still low as no coding has been implemented yet.
  • Development phase: The costs begin to rise if bugs are found during the development phase. Developers may need to spend time debugging and retesting their code, which can reduce velocity and delay other tasks.
  • Testing phase: Detecting a bug during the testing phase can be quite costly. This is because the bug might not only require code changes but also re-testing the entire module or even the whole system to ensure nothing else was affected.
  • Deployment phase: If a bug is found during product deployment, the cost to fix it can be extremely high. It could lead to an extended system outage, roll back procedures, delays to new features, lost revenue, and a negative customer experience which could damage your business’ reputation.
  • Maintenance phase: In this phase, the cost of fixing a bug can be enormous. It involves not only the actual fix but prioritising fixes over new work, comprehensive regression testing and potentially rolling out updates to all users, which could disrupt their usage.

The increased drain of time and resources the later a bug is found in the SDLC highlights the importance of defect prevention through effective requirement gathering and elaboration, design review, and rigorous testing throughout the software development lifecycle.

The difficulty of quantifying the increasing cost of bugs

There have been several attempts to broadly quantify the rising cost of software bugs as they are discovered in the SDLC. Over time, many sources (including Functionize, Celerity, and Reqtest) have quoted either Boehm’s Curve or information from the Systems Sciences Institute at IBM, which both roughly equate to the following relationships:

graph showing the cost of fixing software bugs

  • Requirements phase: The cost to fix a bug is at its lowest, therefore 1x
  • Design phase: The cost increases to about 3x to 5x
  • Coding phase: The cost grows to around 10x
  • Testing phase: The cost can skyrocket to 15x to 20x
  • Post-release: The cost of fixing a bug can be anywhere from 30x to 100x or more of the initial cost

AKF Partner recently weighed in with its 1-10-100 rule:

akf rule of quality control

  • Successful bug prevention during development is your base (x1) cost
  • Bugs caught during quality assurance can have knock-on effects to your codebase and will therefore cost you x10
  • Bugs that impact your customer must be caught and rectified, possibly resulting in system downtown, therefore costing you x100

While all sources agree with the general principle that the cost of fixing a software bug grows significantly the later it is found in development, the exact multiples will vary across organistions, projects, delivery methodologies and technology stacks.

There are no hard and fast rules to govern the broad spectrum of software projects organisations undertake. The cost of bugs can demand radically different solutions depending on their root causes, from amending requirements to altering simple lines of code to changing your team’s skills blend or improving your documentation and review procedures.

The only way to reliably learn the cost of your software bugs is to capture and measure effective quality metrics and use these to evaluate your internal processes and resources.

Speak with a member of our team to learn how Ten10’s Quality and Test Health Check can help you examine all stages of your delivery lifecycle, learn how costly your bugs truly are and what you can do to detect bugs early and prevent them from occurring.

Preventive measures and best practices

As we’ve established, bug prevention and early bug detection is crucial in minimising costs and maintaining project timelines. Here are our best practices that can make a significant difference to your software delivery:

  • Quality metrics: Capturing and measuring useful and informative data regarding the quality of your requirements, code, tests and solution is fundamental to driving quality improvements, measuring the benefit of your interventions and, ultimately, reducing costs.
  • Peer code reviews: Code reviews by peers can help identify bugs that the original developer might have missed. This collaborative approach not facilitates early bug detection and promotes both knowledge sharing and improved coding practices within your team.
  • Thorough requirements analysis: The first step towards preventing bugs is having a clear understanding of what the software is supposed to do. By conducting a thorough requirements analysis that engages with your business and/or user community, potential problems can be identified and addressed before they turn into costly bugs.
  • Rigorous testing: Testing should be an ongoing process throughout the software development lifecycle, not just a final step. Regular, rigorous testing allows for early bug detection and resolution, saving time and resources down the line.
  • Well-defined bug reporting and resolution process: Having a clear process for reporting and resolving bugs ensures that nothing falls through the cracks. It allows for the efficient tracking and handling of bugs, reducing the chances of late-stage bug discovery.
  • Automated testing tools and CI/CD: Implementing automated testing tools can significantly speed up the bug detection process. Moreover, continuous integration and continuous deployment (CI/CD) practices ensure that code changes are regularly built, tested, and merged, thus minimising the risk of bugs making it to the final product.

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