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Keep It Simple, Stupid (KISS): Why Simplicity in Code is a Sign of Great Engineering

Keep It Simple, Stupid (KISS): Why Simplicity in Code is a Sign of Great Engineering

As software engineers, we often face a dilemma: should we showcase our skills by writing intricate, highly optimized, and sometimes cryptic code, or should we prioritize clarity, simplicity, and ease of understanding? Too often, developers lean toward the former, believing that writing complex code demonstrates sophistication and intelligence. However, true craftsmanship in software development lies in simplicity, maintainability, and empathy for the next person who will read your code, which might be you six months from now.

The Essence of KISS

The KISS principle, originally coined by the U.S. Navy in 1960, stands for "Keep It Simple, Stupid." It advocates for simplicity as a core design principle, warning against unnecessary complexity. In software development, this translates to writing code that is straightforward, easy to read, and easy to modify. Code simplicity is not about dumbing down your solutions but about expressing them clearly and efficiently.

Don't Be a Selfish Developer

A selfish developer writes code only they can understand. This kind of developer might use clever tricks, obscure syntax, or overly abstract structures, assuming others (or their future self) will be able to decipher the logic later. This mindset is not just impractical but costly. Maintenance accounts for a significant portion of a software system's total cost. According to Robert C. Martin in Clean Code, code is read far more often than it is written. Therefore, code readability should be a top priority.

Consider the following example:

# Obscure and hard to understand
x = ((y << 2) + z) >> 1

Compare it to:

# Clear and self-explanatory
average = (value1 * 4 + value2) / 2

While the former might be more compact, the latter is significantly easier to read and understand.

The Future Will Thank You

One of the most important reasons to write simple code is for future maintenance. The person who will be tasked with fixing bugs, adding features, or refactoring might be someone new to the project or, more likely, you, months or years later. As I write in my article, "The Importance of Code Comments and Documentation," even the original author can struggle to understand complex logic after enough time has passed.

Related Principles in Software Engineering

YAGNI (You Aren't Gonna Need It)

This principle, like KISS, discourages adding functionality unless it is necessary. It reminds developers to avoid speculative generality and to focus on the current requirements.

DRY (Don't Repeat Yourself)

While DRY emphasizes reducing duplication, it must be balanced with KISS. Abstracting code too early or too aggressively can lead to premature complexity.

Principle of Least Astonishment

This design principle suggests that code should behave in a way that least surprises other developers. Simple, predictable code aligns well with this idea.

Readability and Maintainability

Well-commented, simple code is easier to debug and maintain. In "The Most Common Mistake Software Development Organizations Make," I discuss how neglecting these qualities leads to long-term costs, complexity, and reduced team efficiency.

KISS in Agile and Real-World Projects

In Agile environments, there is often pressure to deliver quickly. Unfortunately, this sometimes results in shortcuts and overly complex patches. As I point out in my article "Software Design: Underrated and Not Practiced," skipping proper design and documentation is a mistake that will haunt teams later. KISS encourages developers to keep solutions simple and well-structured, enabling faster adaptation and more resilient systems.

Final Thoughts

Writing simple code is not a sign of incompetence; it is a mark of professionalism. The best developers write code that others can read, understand, and extend. Embrace the KISS principle not just as a guideline but as a professional ethic. Code simplicity is an investment in long-term software quality.

References

  1. Martin, R. C. (2008). Clean Code: A Handbook of Agile Software Craftsmanship. Prentice Hall.

  2. Beck, K. et al. (2001). Manifesto for Agile Software Development. agilemanifesto.org

  3. Liskov, B., & Guttag, J. (2001). Program Development in Java: Abstraction, Specification, and Object-Oriented Design. Addison-Wesley.

  4. Parnas, D. L. (1972). "On the Criteria to Be Used in Decomposing Systems into Modules." Communications of the ACM, 15(12), 1053–1058.

  5. Wikipedia. KISS Principle. https://en.wikipedia.org/wiki/KISS_principle

  6. White Label Coders Blog. https://whitelabelcoders.com/blog/best-practices-in-programming-based-on-solid-kiss-and-personal-experience


Author: Dr. Sotiris Fanou

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