Introduction to Software Bugs | David Tzemach

Updated: Mar 3

In the software industry, we see bugs as an error in coding. Therefore, we can say that a bug is an error that causes either a specific affected component or the entire system to fail to meet the requirements.


To understand the true meaning of what a software bug is, and to avoid the common misconceptions, we will use these definitions:

  • A human fault A fault related to human activity that causes the system to behave unexpectedly. The initial creation of such mistakes is not evident to the developers. Had they known, they would most likely not have created the fault in the first place.

  • A software bug – A software bug directly results from a human mistake in source code or its design. It represents a problem causing the system to become unstable, producing results that counter user expectations.

  • A system failureA system failure is a direct result of a specific bug causing the system to stop functioning at one level or another.

As you can see, every software bug is related to a human mistake. The simple truth is that they will make mistakes no matter how good developers are. The only remaining question is how those mistakes are reflected in the system once they are used.


Why writing bug reports is essential.

Bug reports are a simple way for project stakeholders to indicate that something in the software is not working as expected. Bug reports allow reported software errors to become a long-living document and manage an incident until its final resolution.


Many teams have abandoned bug reports, as it seems easier to send an e-mail or conduct hallway conversations. This is bad practice, as those teams lose significant advantages, such as:

  • The ability to prioritize and determine which bugs should be addressed first.

  • The ability to track the historical decisions and investigation each incident.

  • A central location to manage all incidents related to the product.

  • Creating dedicated metrics that help both the business and engineering teams promote continuous improvement.

Anatomy of a bug report

No matter how many fields your bug tracking system requires or how much data you try to track, a few essential items differentiate a practical and highly actionable bug report from just wasting time on bug reports that lead you on the wrong path or data that might be ignored.

Below are some of the required fields that should be part of any bug report:


Title – The bug title is perhaps the essential piece of information in the incident report as it allows users to get an idea of the type of bug and the area of impact. A bug title should be short (70-90 characters) and informative enough to summarize the overall incident accurately.

ID – An identifier is usually automatically created by the bug management system, a sequential number for bugs to be easily tracked.

Steps to reproduce – Short, simple, and effective detailed systematic actions to reproduce the bug. A good reproduction scenario will save time by reducing the need to ask further questions to generate missing information.

Environment variables – To save time and ensure the bug will reproduce, the incident report must include the environment in which the bug was found (e.g., OS version, hardware type, etc.).

Created by – When the project consists of multiple teams with many team members, it is helpful to know who logged each bug.


Severity – Severity can be defined as the impact on the product/feature due to the introduction of the bug. It ranges from a minor result such as a cosmetic issue or critical implications that can make the entire system unusable. While the severity level can differ from one organization to another, in my experience, the standard criteria are based on the following severity levels:

  • Severity 1 (Blocker) – An error that prevents the accomplishment of essential system functionality, causes loss of unrecoverable data, or causes repeated system failures.

  • Severity 2 (Critical) – An error that adversely influences the accomplishment of essential system functionality without the availability of an acceptable workaround.

  • Severity 3 (Major) – An error that adversely influences the accomplishment of essential system functionality with an acceptable workaround available within a reasonable time.

  • Severity 4 (Normal) – An error that causes user inconvenience in a specific system flow without significant impact on other system functionality.

  • Severity 5 (Minor) – An error that has a minor impact on specific functionality.

Priority - Priority can be described as the urgency to resolve the bug. here are example priority definitions:

  • P1 (Urgent) – Must be addressed immediately

  • The critical security issue that compromises customer data.

  • The crucial legal issue must be addressed as soon as possible.

  • Important business matters such as integration with partner’s site not working.

  • P2 (Major) – Important but does not represent a catastrophe

  • The significant feature/flow is broken.

  • Major performance issue that impacts the user experience.

  • Under specific conditions, user data may be exposed.

  • P3(Normal) – Fix it after you have addressed P1s and P2s

  • Security issues that are less important with minimal impact on the user.

  • Functionality should be improved (cases that don’t fall into P1/ P2 categories).

  • P4 (Low) – Nice to have

  • Minor cosmetic issues.

  • Typos in low importance areas.

  • Problem with page layouts.

Date created – The bug management system automatically generates when the bug is reported.

Status – This field represents the bug's status from its creation in the system until the teams have closed it.

Date closed – This field is automatically generated by the bug management system when the bug is marked with a specific status, e.g. (verified, by design, etc.).

Expected behavior – The predicted behavior is a short description of the result we expect after performing the steps that triggered the incident.

Actual behavior – This field captures the system's current behavior compared to its expected proper behavior.

Target version – Indication of which future/current version should include the fix of this bug.



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