Technical debt

What is technical debt?

Technical debt is a term used to describe the costs related to choosing an easier, quicker, or more cost-effective but limited solution during software development rather than the optimal approach, which would take more time. Time constraints, budget limitations, or lack of awareness about future needs often cause this. Over time, these shortcuts can accumulate, resulting in fragile and inefficient software and systems.

Common causes of technical debt include:

1. Architectural and design decisions that do not scale well as the application grows
2. Business pressures push the release of code with bugs and deficiencies
3. Code created and released without supporting documentation
4. Deferred refactoring to address code that has become inefficient or difficult to edit
5. Failure to perform proper testing
6. Insufficient definition of functional and technical requirements
7. Lack of a test suite
8. Lack of alignment to standards (e.g., industry-standard features, frameworks, and technologies)
9. Lack of process for assessing and measuring the implications of shortcuts
10. Last-minute specification changes
11. Outsourced software development that requires in-house engineering to refactor or rewrite the code
12. Parallel development tracks with changes hastily merged into a single codebase
13. Poor technological leadership
14. Rush to release software without fully refining the code
15. Selection of outdated or less suitable technologies to achieve short-term goals
16. Tightly coupled components in software limit the ability to adapt to changes

While there is a short-term gain in terms of speed of delivery, debt comes in the form of increased complexity and the cost of future changes to the code. Just like financial debt, technical debt accrues interest. This means that the longer shortcuts remain unresolved, the more time, effort, and resources it will cost to fix later.

Technical debt can lead to a tangled codebase that is hard to understand, maintain, or extend.

This can ultimately slow down new feature development, increase the likelihood of bugs, and impact software performance and stability.

Origin of the term technical debt

Ward Cunningham is credited with coining the term technical debt. He used it during a presentation at the OOPSLA (Object-Oriented Programming, Systems, Languages & Applications) conference in 1992, introducing this concept to describe the compromises in software development that can expedite delivery, but may increase the complexity and cost of future changes, and likening it to financial debt. This metaphor has since become widely accepted in the software industry to express the idea that taking shortcuts now can lead to greater costs later.

How technical debt is acquired during software development

Technical debt is taken on at various points in traditional software development cycles—feature development, alpha, beta, and golden master). What commonly happens is that bugs are discovered during each feature building stage; some are resolved, and others are pushed out to be fixed later in the development cycle.

For instance, during the alpha phase, bug fixes are prioritized according to what is necessary to move to the beta phase with the intention of fixing them once in beta. However, inevitably, new bugs are detected, and the bug fix list continues to grow. This is repeated even when the software reaches the golden master phase. Although the golden master phase is where there should be zero open bugs, it is common to fix known bugs and defer others until the subsequent release.

Technical debt tends to grow, resulting in an ever-increasing number of bugs that become increasingly difficult to address. In addition to leading to user dissatisfaction, these bugs slow development and become even more costly to fix. This is because when a change is initiated in a specific part of code, it often requires additional changes in different parts of the software as well as updates to documentation.

Impact of technical debt beyond development teams

Technical debt is a term that is associated with software development but has implications that impact an entire organization.

1. Increased costs
   Future costs and challenges are a hallmark of technical debt. Like financial debt, technical debt is a cost that must be repaid in the future, which usually entails additional resources, time, and effort needed to resolve issues that result from suboptimal development tactics.
2. Operational deficiencies
   Technical debt can have a detrimental effect on overall operations. It can lead to inefficiencies, reduced productivity, increased maintenance costs, system failures, and security vulnerabilities.
3. Reduced agility
   Technical debt can hinder an organization’s ability to adapt to market changes and evolving technology.
4. Quality issues
   Accumulated technical debt often leads to more bugs and system instability, impacting user experience and potentially leading to customer dissatisfaction.

What is included and not included in technical debt?

Included in technical debt:

1. Code quality issues
   Code quality issues result from poorly written code that is hard to read and maintain, code that does not adhere to best practices, and code that lacks consistency with the overall design of the system. Examples of technical debt from code quality issues are spaghetti code, lack of modularity, duplicated code, and long methods.
2. Deferred refactoring
   Postponing necessary refactoring of code to improve its structure and readability due to time constraints or prioritization issues can accumulate technical debt that leads to increased complexity and decreased productivity as more code is built on top of a shaky foundation.
3. Insufficient testing
   Insufficient testing includes a lack of adequate testing coverage (e.g., unit tests and integration tests), absence of automated testing, and skipped tests to meet deadlines. This can lead to defects and bugs being discovered late in the development process or after deployment.
4. Lack of documentation
   Insufficient or outdated documentation makes it difficult for new team members to understand the system or for existing members to remember the rationale behind certain decisions.
5. Outdated technologies
   The use of outdated technologies, languages, libraries, frameworks, or platforms that are no longer supported can contribute to technical debt, especially if these choices hinder integration with more modern systems or practices.
6. Suboptimal architectural decisions
   Architectural designs that are not scalable or overly complex, as well as those that include outdated or overly rigid system architectures create technical debt by limiting the ability to implement new features or technologies.

Not included in technical debt:

1. Business process inefficiencies
   Inefficiencies in business processes or project management practices are generally outside the scope of technical debt as they are not part of the technical aspects and health of the codebase and architecture.
2. Feature requests and product backlog
   The normal backlog of features or enhancements does not constitute technical debt. While they represent work to be done, they are not the result of previous trade-offs or shortcuts and are not specifically related to quality issues in the code and system design that need rectification.
3. Learning and experimentation
   The process of learning, experimenting, and iterating over time does not constitute technical debt. While early versions of a product might not use the best practices discovered later, the iterative improvement process is a natural part of software development.
4. Normal task prioritization
   Choosing not to implement certain features right away or prioritizing one feature over another based on business needs is not considered technical debt.
5. Unimplemented optimization
   Code that has not been optimized for performance is not automatically classified as technical debt. Premature optimization can be a source of complexity. Technical debt related to unimplemented optimization only arises when known necessary optimizations are continuously deferred.
6. User experience issues
   While improving user interface or user experience is essential, not having the most user-friendly interface from the start is not considered technical debt. However, choices that fundamentally limit the ability to improve user interface or user experience in the future could become technical debt.

Types of technical debt

In software development, technical debt can manifest in a number of different forms. Each type of technical debt presents unique causes, challenges, and consequences and necessitates specific strategies for management and resolution. The following are examples of the many types of technical debt. Note that each type of debt should be considered according to the type of decision or behavior that led to it, such as:

1. Happened-upon technical debt
   This technical debt is inadvertent, with the development team being unaware of its existence until it is exposed during the normal course of performing work or testing.
2. Known technical debt
   The development team is aware of this type of technical debt and has made the deliberate decision to accept it.
3. Targeted technical debt
   The development team knows of this technical debt and it has been targeted for servicing or refactoring.

Build debt refers to the accumulation of complications and inefficiencies in the software development process due to rushed builds and inadequate initial setups. It necessitates future rework to resolve.

Code debt results from issues within the codebase itself. It encompasses poor coding practices, lack of standardization, inadequate code comments, and outdated or inefficient coding techniques. Code debt can hinder code maintenance and scalability.

Defect debt covers unresolved bugs and issues that accumulate in software over time. Addressing these requires significant corrections and testing to ensure software reliability and functionality in the future.

Dependency debt arises from developers’ reliance on outdated or unsupported third-party libraries, frameworks, or tools. This can expose the software to security vulnerabilities and integration challenges.

Design or architecture debt is caused by flawed or outdated software architecture or design. This includes overly complex designs, improper use of patterns, and lack of modularity. Design debt can impede scalability and hinder the introduction of new features.

Documentation debt involves insufficient or outdated documentation. This makes it difficult for both new and existing team members to understand the system and the rationale behind certain decisions, impacting efficiency in maintenance and development.

Infrastructure debt is connected to the environment in which the software operates, such as outdated servers, inadequate deployment practices, or the absence of disaster recovery plans. Infrastructure debt can result in performance issues and increased downtime.

Process debt relates to inefficient or outdated development processes and methodologies. This includes poor communication practices, a lack of agile methodologies, and insufficient collaboration tools.

Requirement debt is caused by incomplete or poorly defined project requirements. This leads to features that don’t meet user needs or expectations, necessitating future revisions and additional development work.

Service or versioning debt arises when services or components are not properly versioned or when legacy systems are utilized without adequate support or integration capabilities.

Technical skills debt, or people debt, occurs when the team lacks certain skills or knowledge, leading to suboptimal solutions. Investing in training and development can help alleviate this debt.

Testing debt results from a lack of sufficient testing, including unit tests, integration tests, and adequate test coverage. This debt increases the risk of defects and bugs in production, potentially leading to system failures and customer dissatisfaction. Testing debt can also be caused by a lack of testing automation.

Categorizing the types of technical debt

The various types of technical debt are generally bucketed into four categories based on both intent and context, as originally defined by Martin Fowler. Technical debt is classified based first on intent (i.e., deliberate or inadvertent), then by whether it is prudent or reckless debt.

1. Prudent and deliberate technical debt
   Choosing to launch a product quickly with the intention of addressing potential issues later introduces a type of technical debt known as prudent and deliberate. This approach is typically adopted when the immediate benefits of a speedy release outweigh the risks associated with delaying the market entry. Teams may consciously accumulate this debt when they calculate that the advantages of earlier market presence surpass the future costs and efforts required to resolve the accrued technical debt.
2. Reckless and deliberate technical debt
   When a team understands the best coding practices yet opts for rapid deployment at the expense of quality, this leads to what’s known as reckless and deliberate technical debt. This decision occurs when the urgency for quick delivery is prioritized above the long-term quality and stability of the product, acknowledging the potential drawbacks, yet choosing speed regardless.
3. Prudent and inadvertent technical debt
   Prudent and inadvertent technical debt arises when a team initially aims to develop optimal code but later discovers a more effective solution post-implementation. This type of debt occurs when insights gained after deploying a solution reveal a superior approach that was not apparent during the initial development phase.
4. Reckless and inadvertent technical debt
   Reckless and inadvertent technical debt results when a team lacking sufficient expertise attempts high-quality coding and unknowingly makes errors in the process. This situation arises when a team implements solutions without fully understanding the implications, leading them into significant complications they initially did not foresee.
   

How do enterprises think about technical debt?

Savvy enterprises approach technical debt with a blend of caution and strategy, recognizing it as an inevitable aspect of software development. The way enterprises think about and manage technical debt involves a number of considerations, including the following.

Continuous monitoring and refactoring

Enterprises monitor and conduct regular code audits to identify and quantify technical debt. This is often coupled with scheduled refactoring initiatives to address debt systematically and ensure that the codebase remains clean, efficient, and maintainable.

Educating stakeholders

Enterprises often invest in educating their stakeholders about the importance of addressing technical debt to ensure there is support for investment in quality and maintenance initiatives. This includes explaining the common causes and implications of technical debt and training development teams on best practices for coding and system design to prevent unnecessary debt accumulation.

Executive awareness and involvement

Unlike smaller companies, in larger enterprises, there is often a higher level of executive awareness and involvement regarding technical debt because decision-makers understand that unmanaged technical debt can significantly impact the organization’s ability to innovate and compete.

Investment in quality and excellence

Enterprises often invest in quality assurance, continuous integration, and deployment practices, as well as adopt coding standards to minimize the creation of new technical debt. This includes regular code reviews, automated testing, and refactoring as part of the development lifecycle.

Risk management

Technical debt is often integrated into the broader risk management frameworks within enterprises. This means assessing the risks associated with technical debt, such as potential security vulnerabilities, system downtime, or degraded performance, and understanding how it aligns with other risks.

Strategic asset management

Enterprises view technical debt as an aspect of their software assets that requires regular management, similar to financial debt. This involves periodic reviews and assessments to determine its impact on the organization and deciding whether to pay it down or live with it based on cost-benefit analyses.

Use technical debt carefully

In and of itself, technical debt is neither good nor bad. It is simply something borrowed that requires repayment. Just like financial debt, taking on technical debt can be the right move in certain circumstances. If it is used, it is important that the development team understands the positives and negatives of the decision to take on technical debt.

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